diff --git a/autoconf/m4/pa_add_flags.m4 b/autoconf/m4/pa_add_flags.m4
index a02868be..766f4820 100644
--- a/autoconf/m4/pa_add_flags.m4
+++ b/autoconf/m4/pa_add_flags.m4
@@ -6,34 +6,38 @@ dnl  by all languages affected by [flagvar], if those languages have
 dnl  been previously seen in the script.
 dnl --------------------------------------------------------------------------
 AC_DEFUN([PA_ADD_FLAGS],
-[
-  AS_VAR_PUSHDEF([old], [_$0_$1_orig])
-  AS_VAR_PUSHDEF([ok], [_$0_$1_ok])
+[ AS_VAR_PUSHDEF([old],[PA_SHSYM([_$0_$1_orig])])
   AS_VAR_PUSHDEF([flags], [$1])
+  AS_VAR_PUSHDEF([cache],[PA_SHSYM([pa_cv_$1_$2])])
 
-  AS_VAR_COPY([old], [flags])
-  AS_VAR_SET([flags], ["$flags $2"])
-  AS_VAR_SET([ok], [yes])
+  AS_VAR_COPY([old],[flags])
 
-  PA_LANG_FOREACH(PA_FLAGS_LANGLIST($1),
-    [AS_VAR_IF([ok], [yes],
-     [AC_MSG_CHECKING([if $]_AC_CC[ accepts $2])
-      PA_BUILD_IFELSE([],
-      [AC_MSG_RESULT([yes])],
-      [AC_MSG_RESULT([no])
-       AS_VAR_SET([ok], [no])])])
-     ])
+  AC_CACHE_VAL([cache],
+  [AS_VAR_APPEND([flags],[' $2'])
+   AS_VAR_SET([cache],[yes])
+   PA_LANG_FOREACH([PA_FLAGS_LANGLIST($1)],
+    [AS_VAR_IF([cache],[yes],
+     [AC_MSG_CHECKING([whether $]_AC_CC[ accepts $2])
+      m4_case([$1],
+      [LDFLAGS],
+      [AC_LINK_IFELSE([AC_LANG_PROGRAM([[]],[[]])],
+		      [],[AS_VAR_SET([cache],[no])])],
+      [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[]],[[]])],
+                      [],[AS_VAR_SET([cache],[no])])])
+     AC_MSG_RESULT([$cache])
+    ])])
+   AS_VAR_COPY([flags],[old])
+  ])
 
- AS_VAR_IF([ok], [yes],
-  [m4_ifnblank([$3],[AS_VAR_SET([flags], ["$old $3"])])
-   m4_foreach_w([_pa_add_flags_flag], [m4_ifblank([$3],[$2],[$3])],
-   [AC_DEFINE(PA_SYM([$1_]_pa_add_flags_flag), 1,
-    [Define to 1 if compiled with the ]_pa_add_flags_flag[ compiler flag])])
-   $4],
-  [AS_VAR_SET([flags], ["$old"])
-   $5])
+  AS_VAR_IF([cache],[yes],
+    [m4_define([_pa_add_flags_newflags],[m4_default([$3],[$2])])dnl
+     AS_VAR_APPEND([flags],[' _pa_add_flags_newflags'])
+     m4_foreach_w([_pa_add_flags_flag],[_pa_add_flags_newflags],
+     [AC_DEFINE(PA_SYM([$1_]_pa_add_flags_flag), 1,
+      [Define to 1 if compiled with ]_pa_add_flags_flag[ in $1])])
+$4],[$5])
 
+  AS_VAR_POPDEF([cache])
   AS_VAR_POPDEF([flags])
-  AS_VAR_POPDEF([ok])
   AS_VAR_POPDEF([old])
 ])
diff --git a/autoconf/m4/pa_add_headers.m4 b/autoconf/m4/pa_add_headers.m4
index daaf7dd0..5c058e4e 100644
--- a/autoconf/m4/pa_add_headers.m4
+++ b/autoconf/m4/pa_add_headers.m4
@@ -5,10 +5,9 @@ dnl Call AC_CHECK_HEADERS_ONCE(), and add to ac_includes_default if found
 dnl --------------------------------------------------------------------------
 AC_DEFUN([_PA_ADD_HEADER],
 [AC_CHECK_HEADERS_ONCE([$1])
-AS_IF([test x$ac_ac_header_$1 = xyes],
+AS_IF([test "x$]PA_SHSYM([ac_cv_header_$1])[" = xyes],
 [ac_includes_default="$ac_includes_default
 #include <$1>"
 ])
 ])
-AC_DEFUN([PA_ADD_HEADERS],
-[m4_map_args_w([$1],[_PA_ADD_HEADER(],[)])])
+AC_DEFUN([PA_ADD_HEADERS],[m4_map_args([_PA_ADD_HEADER],$@)])
diff --git a/autoconf/m4/pa_add_langflags.m4 b/autoconf/m4/pa_add_langflags.m4
index 05c3114f..97364d93 100644
--- a/autoconf/m4/pa_add_langflags.m4
+++ b/autoconf/m4/pa_add_langflags.m4
@@ -1,27 +1,9 @@
 dnl --------------------------------------------------------------------------
 dnl PA_ADD_LANGFLAGS(flag...)
 dnl
-dnl Attempt to add the option in the given list to each compiler flags
-dnl (CFLAGS, CXXFLAGS, ...), if it doesn't break compilation.
+dnl Attempt to add the first accepted option in the given list to each
+dnl compiler flags (CFLAGS, CXXFLAGS, ...).
 dnl --------------------------------------------------------------------------
-m4_defun([_PA_LANGFLAG_VAR],
-[m4_case([$1],
- [C], [CFLAGS],
- [C++], [CXXFLAGS],
- [Fortran 77], [FFLAGS],
- [Fortran], [FCFLAGS],
- [Erlang], [ERLCFLAGS],
- [Objective C], [OBJCFLAGS],
- [Objective C++], [OBJCXXFLAGS],
- [Go], [GOFLAGS],
- [m4_fatal([PA_ADD_LANGFLAGS: Unknown language: $1])])])
-
 AC_DEFUN([PA_ADD_LANGFLAGS],
-[m4_pushdef([_pa_langflags],m4_dquote($1))dnl
-m4_set_foreach(_PA_LANG_SEEN_SET,[_pa_lang],dnl
-[_pa_flag_found=no
- m4_foreach_w([_pa_flag], _pa_langflags,
- [AS_IF([test $_pa_flag_found = no],
-  [PA_ADD_FLAGS(_PA_LANGFLAG_VAR(_pa_lang),_pa_flag,[],[_pa_flag_found=yes])])
-  ])])
-m4_popdef([_pa_langflags])])
+[PA_LANG_FOREACH(PA_LANG_HAVE_FLAGVAR_LIST,
+ [PA_FIND_FLAGS(m4_quote(PA_LANG_FLAGVAR),[$@])])])
diff --git a/autoconf/m4/pa_build_ifelse.m4 b/autoconf/m4/pa_build_ifelse.m4
deleted file mode 100644
index 1aacfcd7..00000000
--- a/autoconf/m4/pa_build_ifelse.m4
+++ /dev/null
@@ -1,16 +0,0 @@
-dnl --------------------------------------------------------------------------
-dnl PA_BUILD_IFELSE(input [,success [,failure]])
-dnl
-dnl  Same as AC_LINK_IFELSE for languages where linking is applicable,
-dnl  otherwise AC_COMPILE_IFELSE.
-dnl
-dnl If the first argument is empty, use _AC_LANG_IO_PROGRAM.
-dnl --------------------------------------------------------------------------
-m4_defun([_PA_BUILD_IFELSE],
-[m4_case(_AC_LANG,
- [Erlang], [AC_COMPILE_IFELSE($@)],
- [AC_LINK_IFELSE($@)])])
-
-AC_DEFUN([PA_BUILD_IFELSE],
-[_PA_BUILD_IFELSE([m4_ifblank([$1],[AC_LANG_SOURCE(_AC_LANG_IO_PROGRAM)],
- [$1])],[$2],[$3])])
diff --git a/autoconf/m4/pa_csym.m4 b/autoconf/m4/pa_csym.m4
index ea0bf809..68334c15 100644
--- a/autoconf/m4/pa_csym.m4
+++ b/autoconf/m4/pa_csym.m4
@@ -7,7 +7,7 @@ dnl to X (so C++ -> CXX). Unlike PA_SYM(), do not compact multiple
 dnl underscores.
 dnl --------------------------------------------------------------------------
 AC_DEFUN([PA_CSYM],
-[m4_toupper(m4_bpatsubsts(m4_quote(m4_toupper(m4_normalize([$*]))),
+[m4_bpatsubsts(m4_quote(m4_toupper(m4_normalize([$*]))),
 [[ ]+],[],[\+],[X],[^\(.\)\([0123456789].*\)$],[[[\1_\2]]],
 [[^ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_]],[_],
-[^._\(.*\)_.$],[[[\1]]]))])
+[^._\(.*\)_.$],[[[\1]]])])
diff --git a/autoconf/m4/pa_flags_langlist.m4 b/autoconf/m4/pa_flags_langlist.m4
index 2ef5ded2..b9a9c78b 100644
--- a/autoconf/m4/pa_flags_langlist.m4
+++ b/autoconf/m4/pa_flags_langlist.m4
@@ -5,7 +5,7 @@ dnl  Return a list of languages affected by the variable flagvar.
 dnl  If flagvar is unknown, assume it affects the current language.
 dnl --------------------------------------------------------------------------
 AC_DEFUN([PA_FLAGS_LANGLIST],
-[m4_dquote(m4_case([$1],
+[m4_case([$1],
 	[CPPFLAGS], [[C],[C++],[Objective C],[Objective C++]],
 	[CFLAGS], [[C]],
 	[CXXFLAGS], [[C++]],
@@ -16,4 +16,4 @@ AC_DEFUN([PA_FLAGS_LANGLIST],
 	[OBJCXXFLAGS], [[Objective C++]],
 	[GOFLAGS], [[Go]],
 	[LDFLAGS], [[C],[C++],[Fortran 77],[Fortran],[Objective C],[Objective C++],[Go]],
-	m4_dquote(_AC_LANG)))])
+	m4_quote(_AC_LANG))])
diff --git a/autoconf/m4/pa_func_attribute.m4 b/autoconf/m4/pa_func_attribute.m4
index a0b69b3a..5b475bfd 100644
--- a/autoconf/m4/pa_func_attribute.m4
+++ b/autoconf/m4/pa_func_attribute.m4
@@ -17,7 +17,7 @@ AC_DEFUN([_PA_FUNC_ATTRIBUTE],
  m4_define([_pa_fam],ifelse([$2],[],[],[(m4_join([,],m4_for(_pa_n,1,m4_count($2),1,[m4_quote([x]_pa_n),])))]))
  m4_define([_pa_suf],ifelse([$2],[],[],[m4_count($2)]))
  m4_define([_pa_mac],ifelse([$6],[],[$1_func]_pa_suf,[$6]))
- AC_MSG_CHECKING([if $CC supports the $1]_pa_faa[ function attribute])
+ AC_MSG_CHECKING([whether $]_AC_CC[ supports the $1]_pa_faa[ function attribute])
  AC_COMPILE_IFELSE([AC_LANG_SOURCE([
 AC_INCLUDES_DEFAULT
 PA_ATTRIBUTE_SYNTAX
@@ -50,7 +50,7 @@ AC_DEFUN([_PA_FUNC_PTR_ATTRIBUTE],
  m4_define([_pa_fam],ifelse([$2],[],[],[(m4_join([,],m4_for(_pa_n,1,m4_count($2),1,[m4_quote([x]_pa_n),])))]))
  m4_define([_pa_suf],ifelse([$2],[],[],[m4_count($2)]))
  m4_define([_pa_mac],ifelse([$6],[],[$1_func]_pa_suf,[$6])_ptr)
- AC_MSG_CHECKING([if $CC supports the $1]_pa_faa[ function attribute on pointers])
+ AC_MSG_CHECKING([whether $]_AC_CC[ supports the $1]_pa_faa[ function attribute on pointers])
  AC_COMPILE_IFELSE([AC_LANG_SOURCE([
 AC_INCLUDES_DEFAULT
 PA_ATTRIBUTE_SYNTAX
diff --git a/autoconf/m4/pa_func_attribute_error.m4 b/autoconf/m4/pa_func_attribute_error.m4
index bd6a12a7..035c2c93 100644
--- a/autoconf/m4/pa_func_attribute_error.m4
+++ b/autoconf/m4/pa_func_attribute_error.m4
@@ -11,7 +11,7 @@ dnl This doesn't use a function pointer because there is no need:
 dnl the error function will never be a function pointer.
 dnl --------------------------------------------------------------------------
 AC_DEFUN([PA_FUNC_ATTRIBUTE_ERROR],
-[AC_MSG_CHECKING([if $CC supports the error function attribute])
+[AC_MSG_CHECKING([whether $]_AC_CC[ supports the error function attribute])
  AC_COMPILE_IFELSE([AC_LANG_SOURCE([
 AC_INCLUDES_DEFAULT
 PA_ATTRIBUTE_SYNTAX
diff --git a/autoconf/m4/pa_have_func.m4 b/autoconf/m4/pa_have_func.m4
index d32b1fd1..46203e6b 100644
--- a/autoconf/m4/pa_have_func.m4
+++ b/autoconf/m4/pa_have_func.m4
@@ -13,22 +13,25 @@ AC_DEFUN([_PA_HAVE_FUNC_INCLUDE],
 ])])
 
 AC_DEFUN([PA_HAVE_FUNC],
-[AC_CACHE_CHECK([for $1], [pa_cv_func_$1],
+[AS_VAR_PUSHDEF([cache],[PA_SHSYM([pa_cv_func_$1])])
+ AC_CACHE_CHECK([for $1], [cache],
 [
 m4_ifnblank([$3],[AC_CHECK_HEADERS_ONCE($3)])dnl
 m4_pushdef([pa_func_args],m4_strip(m4_default([$2],[(0)])))dnl
 m4_pushdef([pa_func_type],m4_default([$4],[void]))dnl
 AC_LINK_IFELSE([AC_LANG_PROGRAM(
+[AC_INCLUDES_DEFAULT]
 m4_map_args_w([$3], [_PA_HAVE_FUNC_INCLUDE(], [)]),
 m4_cond(pa_func_type,[void],[
     (void)$1]pa_func_args[;],[
     ]pa_func_type[ tmp = $1]pa_func_args[;
     (void)tmp;])
-)],[pa_cv_func_$1=yes],[pa_cv_func_$1=no])
+)],[AS_VAR_SET([cache],[yes])],[AS_VAR_SET([cache],[no])])
 m4_popdef([pa_func_args])dnl
 m4_popdef([pa_func_type])dnl
 ])
 
-AS_IF([test "x$pa_cv_func_$1" = xyes],
+AS_VAR_IF([cache],[yes],
 [AC_DEFINE(PA_CSYM([HAVE_$1]), 1,
-["Define to 1 if you have the `$1' intrinsic function."])])])
+["Define to 1 if you have the `$1' intrinsic function."])])
+])
diff --git a/autoconf/m4/pa_lang_flagvar.m4 b/autoconf/m4/pa_lang_flagvar.m4
new file mode 100644
index 00000000..269d4e3b
--- /dev/null
+++ b/autoconf/m4/pa_lang_flagvar.m4
@@ -0,0 +1,21 @@
+dnl --------------------------------------------------------------------------
+dnl PA_LANG_FLAGVAR([language])
+dnl
+dnl  Return the name of the compiler flag variable for the current or
+dnl  specified language. Returns empty if the variable name is not known.
+dnl --------------------------------------------------------------------------
+AC_DEFUN([PA_LANG_FLAGVAR],
+[m4_case(m4_quote(m4_default([$1],m4_quote(_AC_LANG))),
+	[C], [CFLAGS],
+	[C++], [CXXFLAGS],
+	[Fortran 77], [FFLAGS],
+	[Fortran], [FCFLAGS],
+	[Erlang], [ERLCFLAGS],
+	[Objective C], [OBJCFLAGS],
+	[Objective C++], [OBJCXXFLAGS],
+	[Go], [GOFLAGS],
+	[m4_fatal([PA_LANG_FLAGVAR: Unknown language: $1])])])
+
+AC_DEFUN([PA_LANG_HAVE_FLAGVAR_LIST],
+	 [[[C], [C++], [Fortran 77], [Fortran], [Erlang],
+	  [Objective C], [Objective C++], [Go]]])
diff --git a/autoconf/m4/pa_lang_foreach.m4 b/autoconf/m4/pa_lang_foreach.m4
index 650913d8..5807db5a 100644
--- a/autoconf/m4/pa_lang_foreach.m4
+++ b/autoconf/m4/pa_lang_foreach.m4
@@ -4,12 +4,14 @@ dnl
 dnl  Expand [body] for each language encountered in the configure script also
 dnl  present in [subset], or all if [subset] is empty
 dnl --------------------------------------------------------------------------
-AC_DEFUN([_PA_LANG_DO],dnl
-[AC_LANG([$2])dnl
-$1])
+AC_DEFUN([_PA_LANG_FOREACH],
+[m4_pushdef([pa_lang_for_each])dnl
+m4_foreach([pa_lang_for_each],$1,[dnl
+AC_LANG_PUSH(pa_lang_for_each)
+$2
+AC_LANG_POP(pa_lang_for_each)
+])dnl
+m4_popdef([pa_lang_for_each])])
 
-AC_DEFUN([PA_LANG_FOREACH],dnl
-[m4_pushdef([_pa_lang_foreach_current],[_AC_LANG])dnl
-m4_map_args([m4_curry([_PA_LANG_DO],[$2])],m4_unquote(PA_LANG_SEEN_LIST($1)))dnl
-AC_LANG(_pa_lang_foreach_current)dnl
-m4_popdef([_pa_lang_foreach_current])])
+AC_DEFUN([PA_LANG_FOREACH],
+[_PA_LANG_FOREACH(m4_dquote(PA_LANG_SEEN_LIST(m4_dquote($1))),[$2])])
diff --git a/autoconf/m4/pa_lang_seen_list.m4 b/autoconf/m4/pa_lang_seen_list.m4
index d5240136..b0123c1a 100644
--- a/autoconf/m4/pa_lang_seen_list.m4
+++ b/autoconf/m4/pa_lang_seen_list.m4
@@ -7,14 +7,10 @@ dnl
 dnl This relies on overriding _AC_LANG_SET(from, to),
 dnl the internal implementation of _AC_LANG.
 dnl --------------------------------------------------------------------------
-m4_ifndef([_PA_LANG_SET],
-[m4_rename([_AC_LANG_SET], [_PA_LANG_SET])dnl
-m4_defun([_AC_LANG_SET], [m4_set_add([_PA_LANG_SEEN_SET],[$2])dnl
-_PA_LANG_SET($@)])])
-
 AC_DEFUN([PA_LANG_SEEN_LIST],
+[m4_ifblank([$1],
+[m4_define([_pa_lang_seen_list_out],m4_dquote(m4_set_list(PA_LANG_SEEN_SET)))],
 [m4_set_delete([_pa_lang_seen_subset])dnl
-m4_pushdef([_pa_lang_seen_subset_list],m4_ifnblank([$1],[$1],m4_dquote(m4_set_list([_PA_LANG_SEEN_SET]))))dnl
-m4_set_add_all([_pa_lang_seen_subset],_pa_lang_seen_subset_list)dnl
-m4_cdr(m4_set_intersection([_pa_lang_seen_subset],[_PA_LANG_SEEN_SET]))dnl
-m4_popdef([_pa_lang_seen_subset_list])])
+m4_set_add_all([_pa_lang_seen_subset],$1)dnl
+m4_define([_pa_lang_seen_list_out],m4_dquote(m4_cdr(m4_set_intersection([_pa_lang_seen_subset],PA_LANG_SEEN_SET))))dnl
+m4_dquote(_pa_lang_seen_list_out)])])
diff --git a/autoconf/m4/pa_lang_seen_set.m4 b/autoconf/m4/pa_lang_seen_set.m4
new file mode 100644
index 00000000..c1bb126a
--- /dev/null
+++ b/autoconf/m4/pa_lang_seen_set.m4
@@ -0,0 +1,19 @@
+dnl --------------------------------------------------------------------------
+dnl PA_LANG_SEEN_SET
+dnl
+dnl  Set of the languages that have been used in the configuration.
+dnl
+dnl This relies on overriding _AC_LANG_SET(from, to),
+dnl the internal implementation of _AC_LANG.
+dnl
+dnl The very first language transition [] -> [C] is ignored, because
+dnl it is done from AC_INIT regardless of any user specified language.
+dnl --------------------------------------------------------------------------
+
+m4_ifndef([_PA_LANG_SET],
+[m4_rename([_AC_LANG_SET], [_PA_LANG_SET])
+m4_set_delete([_pa_lang_seen_set])
+m4_defun([_AC_LANG_SET],
+[m4_ifnblank([$1],[m4_set_add([_pa_lang_seen_set],[$2])])_PA_LANG_SET($@)])])
+
+AC_DEFUN([PA_LANG_SEEN_SET],[[_pa_lang_seen_set]])
diff --git a/autoconf/m4/pa_option_debug.m4 b/autoconf/m4/pa_option_debug.m4
index ae7d9db8..6b1a40b3 100644
--- a/autoconf/m4/pa_option_debug.m4
+++ b/autoconf/m4/pa_option_debug.m4
@@ -6,8 +6,8 @@ dnl --enable-debug is set or not. Some flags are set regardless...
 dnl --------------------------------------------------------------------------
 AC_DEFUN([PA_OPTION_DEBUG],
 [PA_ARG_DISABLED([gdb], [disable gdb debug extensions],
- [PA_ADD_LANGFLAGS([-g3])], [PA_ADD_LANGFLAGS([-ggdb3 -g3])])
+ [PA_ADD_LANGFLAGS([-g3])], [PA_ADD_LANGFLAGS([-ggdb3],[-g3])])
  PA_ARG_ENABLED([debug], [optimize for debugging],
- [PA_ADD_LANGFLAGS([-Og -O0])
+ [PA_ADD_LANGFLAGS([-Og],[-O0])
   $1],
  [$2])])
diff --git a/autoconf/m4/pa_option_gc.m4 b/autoconf/m4/pa_option_gc.m4
index febb61bf..863cadb9 100644
--- a/autoconf/m4/pa_option_gc.m4
+++ b/autoconf/m4/pa_option_gc.m4
@@ -9,6 +9,6 @@ AC_DEFUN([PA_OPTION_GC],
  [do not compile with dead code garbage collection support],
  [],
  [PA_ADD_LDFLAGS([-Wl,--as-needed])
-  PA_ADD_CFLAGS([-ffunction-sections])
-  PA_ADD_CFLAGS([-fdata-sections])
+  PA_ADD_LANGFLAGS([-ffunction-sections])
+  PA_ADD_LANGFLAGS([-fdata-sections])
   PA_ADD_LDFLAGS([-Wl,--gc-sections])])])
diff --git a/autoconf/m4/pa_option_lto.m4 b/autoconf/m4/pa_option_lto.m4
index ea5456b6..88f361b8 100644
--- a/autoconf/m4/pa_option_lto.m4
+++ b/autoconf/m4/pa_option_lto.m4
@@ -7,15 +7,15 @@ dnl  but that could change in the future -- to force disabled by default,
 dnl  set to "no".
 dnl --------------------------------------------------------------------------
 AC_DEFUN([PA_OPTION_LTO],
-[PA_ARG_BOOL([lto],
+[AC_BEFORE([$0],[AC_PROG_AR])dnl
+ AC_BEFORE([$0],[AC_PROG_RANLIB])dnl
+ PA_ARG_BOOL([lto],
  [Try to enable link-time optimization for this compiler],
- [$1],
- [PA_ADD_LANGFLAGS([-flto=auto -flto])
-PA_ADD_LANGFLAGS([-ffat-lto-objects])
-dnl Note: we use _PROG rather than _TOOL since we are prepending the full
-dnl CC name which ought to already contain the host triplet if needed
-   ccbase=`echo "$CC" | awk '{ print $1; }'`
-   AC_CHECK_PROGS(CC_AR, [${ccbase}-ar], [$ac_cv_prog_AR])
-   AR="$CC_AR"
-   AC_CHECK_PROGS(CC_RANLIB, [${ccbase}-ranlib], [$ac_cv_prog_RANLIB])
-   RANLIB="$CC_RANLIB"])])
+ [m4_default([$1],[no])],
+ [PA_FIND_FLAGS([-flto=auto],[-flto])
+  PA_FIND_FLAGS([-ffat-lto-objects])
+  PA_FIND_FLAGS([-fuse-linker-plugin])
+
+  AS_IF([test x$ac_compiler_gnu = xyes],
+  [AC_CHECK_TOOL(AR, [gcc-ar], [ar], [:])
+   AC_CHECK_TOOL(RANLIB, [gcc-ranlib], [ranlib], [:])])])])
diff --git a/autoconf/m4/pa_option_sanitizer.m4 b/autoconf/m4/pa_option_sanitizer.m4
index 17ab0ad0..d096e16f 100644
--- a/autoconf/m4/pa_option_sanitizer.m4
+++ b/autoconf/m4/pa_option_sanitizer.m4
@@ -6,6 +6,6 @@ dnl --------------------------------------------------------------------------
 AC_DEFUN([PA_OPTION_SANITIZER],
 [PA_ARG_ENABLED([sanitizer],
  [compile with sanitizers enabled],
- [PA_ADD_CFLAGS([-fno-omit-frame-pointer])
-  PA_ADD_CFLAGS([-fsanitize=address])
-  PA_ADD_CFLAGS([-fsanitize=undefined])])])
+ [PA_ADD_LANGFLAGS([-fno-omit-frame-pointer])
+  PA_ADD_LANGFLAGS([-fsanitize=address])
+  PA_ADD_LANGFLAGS([-fsanitize=undefined])])])
diff --git a/autoconf/m4/pa_shsym.m4 b/autoconf/m4/pa_shsym.m4
new file mode 100644
index 00000000..0bf02924
--- /dev/null
+++ b/autoconf/m4/pa_shsym.m4
@@ -0,0 +1,14 @@
+dnl --------------------------------------------------------------------------
+dnl PA_SHSYM(...)
+dnl
+dnl Convert a (semi-) arbitrary string to a shell symbol
+dnl Convert non-shell characters to underscores, except + which is converted
+dnl to x (so C++ -> cxx). Unlike PA_SYM(), do not compact multiple
+dnl underscores.
+dnl
+dnl This currently differs from PA_CSYM only in not doing case conversion.
+dnl --------------------------------------------------------------------------
+AC_DEFUN([PA_SHSYM],
+[m4_bpatsubsts(m4_quote(m4_normalize([$*])),
+[[ ]+],[],[\+],[x],[[^abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_]],[_],
+[^._\(.*\)_.$],[[[\1]]])])