asterisk: update the description around -fblocks failing on clang arches,

patch and tweak the port Makefile to make it easier to test this

telephony/asterisk/Makefile

@@ -1,4 +1,4 @@
-# $OpenBSD: Makefile,v 1.324 2020/09/04 21:22:41 sthen Exp $
+# $OpenBSD: Makefile,v 1.325 2020/09/12 19:35:37 sthen Exp $
 
 COMMENT-main=	open source multi-protocol PBX and telephony toolkit
 
@@ -46,10 +46,12 @@ DPB_PROPERTIES=	parallel
 #    echo 'int main(){return ^{return 42;}();}' | \
 #         clang -o /tmp/blockstest -fblocks -x c -L/usr/local/lib -lBlocksRuntime -
 #
-# -> undefined reference to `_NSConcreteGlobalBlock'
+# -> undefined reference to `_NSConcreteGlobalBlock' (also can be tested
+# on ld.lld arches by adding "-fuse-ld=bfd")
 #
 # - runtime fails on ld.lld arches: dlopen()ing the .so modules results in
-# undefined symbols from the BlocksRuntime lib.
+# undefined symbols (same symbols as ld.bfd detects as missing) from the
+# BlocksRuntime lib.
 #
 # So, as things stand, this requires building with gcc.
 #
@@ -180,10 +182,6 @@ CONFIGURE_ARGS+=	--with-imap=no
 ## multipackages:
 .include <bsd.port.arch.mk>
 
-#.if ${PROPERTIES:Mclang}
-#BUILD_DEPENDS+=		devel/blocksruntime
-#.endif
-
 # calendar
 COMMENT-calendar=	calendar support for Asterisk
 WANTLIB-calendar=	crypto expat ical iconv intl iksemel lzma
@@ -338,3 +336,9 @@ post-install:
 	@find ${WRKINST}/opt -type d -delete
 
 .include <bsd.port.mk>
+
+.if ${CHOSEN_COMPILER} == ports-gcc
+CFLAGS+=		-ftrampolines
+.else
+BUILD_DEPENDS+=		devel/blocksruntime
+.endif

telephony/asterisk/patches/patch-Makefile

@@ -1,4 +1,10 @@
-$OpenBSD: patch-Makefile,v 1.44 2020/03/29 15:42:27 sthen Exp $
+$OpenBSD: patch-Makefile,v 1.45 2020/09/12 19:35:37 sthen Exp $
+
+- don't force compiler flags
+- don't unconditionally set -ftrampolines, it is gcc-only.
+(Blocksruntime isn't working correctly on OpenBSD anyway so clang
+is not yet an option, but patched away here to allow for easier
+testing, and added-back in the port Makefile).
 
 Index: Makefile
 --- Makefile.orig
@@ -22,3 +28,12 @@ Index: Makefile
    endif
  endif
  
+@@ -231,7 +233,7 @@ ifeq ($(OSARCH),NetBSD)
+ endif
+ 
+ ifeq ($(OSARCH),OpenBSD)
+-  _ASTCFLAGS+=-pthread -ftrampolines
++  _ASTCFLAGS+=-pthread
+ endif
+ 
+ ifeq ($(OSARCH),linux-uclibc)

telephony/asterisk/patches/patch-autoconf_ast_check_raii_m4

@@ -0,0 +1,16 @@
+$OpenBSD: patch-autoconf_ast_check_raii_m4,v 1.4 2020/09/12 19:35:37 sthen Exp $
+
+Index: autoconf/ast_check_raii.m4
+--- autoconf/ast_check_raii.m4.orig
++++ autoconf/ast_check_raii.m4
+@@ -41,6 +41,10 @@ AC_DEFUN([AST_CHECK_RAII], [
+ 				AST_CLANG_BLOCKS_LIBS="-lBlocksRuntime"
+ 				AST_CLANG_BLOCKS="-fblocks"
+ 				AC_MSG_RESULT(yes)
++			elif test "`echo 'int main(){return ^{return 42;}();}' | ${CC} -o /dev/null -L/usr/local/lib -fblocks -x c -lBlocksRuntime - 2>&1`" = ""; then
++				AST_CLANG_BLOCKS_LIBS="-L/usr/local/lib -lBlocksRuntime"
++				AST_CLANG_BLOCKS="-fblocks"
++				AC_MSG_RESULT(yes)
+ 			else
+ 				AC_MSG_ERROR([BlocksRuntime is required for clang, please install libblocksruntime])
+ 			fi