Fix alloca definition when using gcc on non-gnu systems.

* configure.in: Use the code sequence indicated by "info autoconf"
for alloca (bug#6170).

3 files changed, 32 insertions, 18 deletions

diff --git a/ChangeLog b/ChangeLog
index 5b0432f679f..9d2fe0b233c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2010-06-02  Dan Nicolaescu  <dann@ics.uci.edu>
+
+        Fix alloca definition when using gcc on non-gnu systems.
+        * configure.in: Use the code sequence indicated by "info autoconf"
+        for alloca (bug#6170).
+
 2010-05-30  Stefan Monnier  <monnier@iro.umontreal.ca>
 
         * .bzrignore: Ignore new files from trunk, which appear if you use
diff --git a/configure.in b/configure.in
index 9694a91739f..2e31641f25f 100644
--- a/configure.in
+++ b/configure.in
@@ -3604,15 +3604,19 @@ extern char *getenv ();
 #ifdef HAVE_STDLIB_H
 #include <stdlib.h>
 #endif
-#ifndef __GNUC__
-# ifdef HAVE_ALLOCA_H
-#  include <alloca.h>
-# else /* AIX files deal with #pragma.  */
-#  ifndef alloca /* predefined by HP cc +Olibcalls */
-char *alloca ();
-#  endif
-# endif /* HAVE_ALLOCA_H */
-#endif /* __GNUC__ */
+#ifdef HAVE_ALLOCA_H
+# include <alloca.h>
+#elif defined __GNUC__
+# define alloca __builtin_alloca
+#elif defined _AIX
+# define alloca __alloca
+#else
+# include <stddef.h>
+# ifdef  __cplusplus
+extern "C"
+# endif
+void *alloca (size_t);
+#endif
 #ifndef HAVE_SIZE_T
 typedef unsigned size_t;
 #endif
diff --git a/src/config.in b/src/config.in
index 9d845027db4..16d788fd7a2 100644
--- a/src/config.in
+++ b/src/config.in
@@ -1164,15 +1164,19 @@ extern char *getenv ();
 #ifdef HAVE_STDLIB_H
 #include <stdlib.h>
 #endif
-#ifndef __GNUC__
-# ifdef HAVE_ALLOCA_H
-#  include <alloca.h>
-# else /* AIX files deal with #pragma.  */
-#  ifndef alloca /* predefined by HP cc +Olibcalls */
-char *alloca ();
-#  endif
-# endif /* HAVE_ALLOCA_H */
-#endif /* __GNUC__ */
+#ifdef HAVE_ALLOCA_H
+# include <alloca.h>
+#elif defined __GNUC__
+# define alloca __builtin_alloca
+#elif defined _AIX
+# define alloca __alloca
+#else
+# include <stddef.h>
+# ifdef  __cplusplus
+extern "C"
+# endif
+void *alloca (size_t);
+#endif
 #ifndef HAVE_SIZE_T
 typedef unsigned size_t;
 #endif