diff --git a/Makefile.config.in b/Makefile.config.in
index 10e4330d..4a6b6cf1 100644
--- a/Makefile.config.in
+++ b/Makefile.config.in
@@ -134,7 +134,7 @@ CONFIG_NLS = @CONFIG_NLS@
 CONFIG_NNTP = @CONFIG_NNTP@
 CONFIG_NO_ROOT_EXEC = @CONFIG_NO_ROOT_EXEC@
 CONFIG_OPENSSL = @CONFIG_OPENSSL@
-CONFIG_OS2 = @CONFIG_OS2@
+CONFIG_OS_OS2 = @CONFIG_OS_OS2@
 CONFIG_OWN_LIBC = @CONFIG_OWN_LIBC@
 CONFIG_SCRIPTING_PERL = @CONFIG_SCRIPTING_PERL@
 CONFIG_POD2HTML = @CONFIG_POD2HTML@
diff --git a/config/m4/os2.m4 b/config/m4/os2.m4
index 6a46400a..7e3bd821 100644
--- a/config/m4/os2.m4
+++ b/config/m4/os2.m4
@@ -1,5 +1,5 @@
 
-AC_DEFUN([EL_CONFIG_OS2],
+AC_DEFUN([EL_CONFIG_OS_OS2],
 [
 	AC_MSG_CHECKING([for OS/2 threads])
 
diff --git a/configure.in b/configure.in
index c55c0d71..242db08b 100644
--- a/configure.in
+++ b/configure.in
@@ -151,16 +151,16 @@ AC_SUBST(CONFIG_RISCOS)
 EL_CHECK_COMPILER_MACROS(CONFIG_WIN32, [WIN32], [_WIN32 __WIN32__])
 AC_SUBST(CONFIG_WIN32)
 
-EL_CHECK_COMPILER_MACROS(CONFIG_OS2, [EMX], [__EMX__])
-AC_SUBST(CONFIG_OS2)
-test "$CONFIG_OS2" = yes && LDFLAGS=`echo "$LDFLAGS" | sed "s/-Zexe//g"`
+EL_CHECK_COMPILER_MACROS(CONFIG_OS_OS2, [EMX], [__EMX__])
+AC_SUBST(CONFIG_OS_OS2)
+test "$CONFIG_OS_OS2" = yes && LDFLAGS=`echo "$LDFLAGS" | sed "s/-Zexe//g"`
 
 AC_MSG_CHECKING([for UNIX])
 dnl FIXME: some depend kind of mechanism
 if test "$CONFIG_BEOS" = no && \
    test "$CONFIG_RISCOS" = no && \
    test "$CONFIG_WIN32" = no && \
-   test "$CONFIG_OS2" = no; then
+   test "$CONFIG_OS_OS2" = no; then
 	EL_CONFIG(CONFIG_UNIX, [UNIX])
 else
 	CONFIG_UNIX=no
@@ -484,8 +484,8 @@ dnl ===================================================================
 dnl Checks for OS/2
 dnl ===================================================================
 
-if test "$CONFIG_OS2" = yes; then
-	EL_CONFIG_OS2
+if test "$CONFIG_OS_OS2" = yes; then
+	EL_CONFIG_OS_OS2
 fi
 
 dnl ===================================================================
@@ -1239,8 +1239,8 @@ AC_ARG_ENABLE(weehoofooboomookerchoo,
 
 dnl == EMX hack
 
-test "$CONFIG_OS2" = yes && LDFLAGS="$LDFLAGS -Zexe"
-test "$CONFIG_OS2" = yes && LDFLAGS=`echo "$LDFLAGS" | sed "s/-Zbin-files//g"`
+test "$CONFIG_OS_OS2" = yes && LDFLAGS="$LDFLAGS -Zexe"
+test "$CONFIG_OS_OS2" = yes && LDFLAGS=`echo "$LDFLAGS" | sed "s/-Zbin-files//g"`
 
 
 dnl ===================================================================
diff --git a/src/ecmascript/spidermonkey/util.h b/src/ecmascript/spidermonkey/util.h
index b787251b..9caf547f 100644
--- a/src/ecmascript/spidermonkey/util.h
+++ b/src/ecmascript/spidermonkey/util.h
@@ -5,7 +5,7 @@
 /* For wild SpiderMonkey installations. */
 #ifdef CONFIG_BEOS
 #define XP_BEOS
-#elif CONFIG_OS2
+#elif CONFIG_OS_OS2
 #define XP_OS2
 #elif CONFIG_RISCOS
 #error Out of luck, buddy!
diff --git a/src/osdep/Makefile b/src/osdep/Makefile
index 5ac1390b..c8187f76 100644
--- a/src/osdep/Makefile
+++ b/src/osdep/Makefile
@@ -3,7 +3,7 @@ include $(top_builddir)/Makefile.config
 INCLUDES += $(X_CFLAGS)
 
 SUBDIRS-$(CONFIG_BEOS)		+= beos
-SUBDIRS-$(CONFIG_OS2)		+= os2
+SUBDIRS-$(CONFIG_OS_OS2)		+= os2
 SUBDIRS-$(CONFIG_RISCOS)	+= riscos
 SUBDIRS-$(CONFIG_UNIX)		+= unix
 SUBDIRS-$(CONFIG_WIN32)		+= win32
diff --git a/src/osdep/newwin.c b/src/osdep/newwin.c
index 8d82e6ff..1801872f 100644
--- a/src/osdep/newwin.c
+++ b/src/osdep/newwin.c
@@ -26,7 +26,7 @@ const struct open_in_new open_in_new[] = {
 	{ ENV_XWIN,	XTERM_CMD,		    N_("~Xterm") },
 	{ ENV_TWIN,	DEFAULT_TWTERM_CMD,	    N_("T~wterm") },
 	{ ENV_SCREEN,	DEFAULT_SCREEN_CMD,	    N_("~Screen") },
-#ifdef CONFIG_OS2
+#ifdef CONFIG_OS_OS2
 	{ ENV_OS2VIO,	DEFAULT_OS2_WINDOW_CMD,	    N_("~Window") },
 	{ ENV_OS2VIO,	DEFAULT_OS2_FULLSCREEN_CMD, N_("~Full screen") },
 #endif
diff --git a/src/osdep/os2/os2.h b/src/osdep/os2/os2.h
index 838ef9de..99b3f6d9 100644
--- a/src/osdep/os2/os2.h
+++ b/src/osdep/os2/os2.h
@@ -2,7 +2,7 @@
 #ifndef EL__OSDEP_OS2_OS2_H
 #define EL__OSDEP_OS2_OS2_H
 
-#ifdef CONFIG_OS2
+#ifdef CONFIG_OS_OS2
 
 struct terminal;
 
diff --git a/src/osdep/os2/sysinfo.h b/src/osdep/os2/sysinfo.h
index e64fc3f8..0c195c6e 100644
--- a/src/osdep/os2/sysinfo.h
+++ b/src/osdep/os2/sysinfo.h
@@ -2,7 +2,7 @@
 #ifndef EL__OSDEP_OS2_SYSINFO_H
 #define EL__OSDEP_OS2_SYSINFO_H
 
-#ifdef CONFIG_OS2
+#ifdef CONFIG_OS_OS2
 
 #define SYSTEM_NAME	"OS/2"
 #define SYSTEM_STR	"os2"
diff --git a/src/osdep/osdep.c b/src/osdep/osdep.c
index 1503f84d..a8b74f64 100644
--- a/src/osdep/osdep.c
+++ b/src/osdep/osdep.c
@@ -185,7 +185,7 @@ get_shell(void)
 
 /* Terminal size */
 
-#if !defined(CONFIG_OS2) && !defined(CONFIG_WIN32)
+#if !defined(CONFIG_OS_OS2) && !defined(CONFIG_WIN32)
 
 static void
 sigwinch(void *s)
@@ -245,7 +245,7 @@ c_pipe(int *fd)
 	return pipe(fd);
 }
 
-#elif defined(CONFIG_OS2) || defined(CONFIG_WIN32)
+#elif defined(CONFIG_OS_OS2) || defined(CONFIG_WIN32)
 
 void
 set_bin(int fd)
@@ -332,7 +332,7 @@ is_xterm(void)
 
 unsigned int resize_count = 0;
 
-#ifndef CONFIG_OS2
+#ifndef CONFIG_OS_OS2
 
 #if !(defined(CONFIG_BEOS) && defined(HAVE_SETPGID)) && !defined(CONFIG_WIN32)
 
@@ -729,7 +729,7 @@ init_osdep(void)
 
 #endif
 
-#if defined(CONFIG_UNIX) || defined(CONFIG_OS2) || defined(CONFIG_RISCOS)
+#if defined(CONFIG_UNIX) || defined(CONFIG_OS_OS2) || defined(CONFIG_RISCOS)
 
 void
 terminate_osdep(void)
@@ -838,7 +838,7 @@ can_resize_window(int environment)
 	return !!(environment & (ENV_OS2VIO | ENV_XWIN));
 }
 
-#ifndef CONFIG_OS2
+#ifndef CONFIG_OS_OS2
 int
 can_open_os_shell(int environment)
 {
diff --git a/src/osdep/system.h b/src/osdep/system.h
index 32ac78f6..9cd72c46 100644
--- a/src/osdep/system.h
+++ b/src/osdep/system.h
@@ -2,7 +2,7 @@
 #define EL__OSDEP_SYSTEM_H
 
 #if !defined(CONFIG_BEOS) \
-     && !defined(CONFIG_OS2) \
+     && !defined(CONFIG_OS_OS2) \
      && !defined(CONFIG_RISCOS) \
      && !defined(CONFIG_UNIX) \
      && !defined(CONFIG_WIN32)
diff --git a/src/util/secsave.c b/src/util/secsave.c
index 448d5e74..3b3a306e 100644
--- a/src/util/secsave.c
+++ b/src/util/secsave.c
@@ -261,7 +261,7 @@ secure_close(struct secure_save_info *ssi)
 	}
 
 	if (ssi->secure_save && ssi->file_name && ssi->tmp_file_name) {
-#ifdef CONFIG_OS2
+#ifdef CONFIG_OS_OS2
 		/* OS/2 needs this, however it breaks atomicity on
 		 * UN*X. */
 		unlink(ssi->file_name);