Fix invalid pointer arithmetic.

[nmh] / m4 / cppflags.m4

diff --git a/m4/cppflags.m4 b/m4/cppflags.m4
index d2cd351e26a67a313c4b398fe524e08d700e61ab..8e7bc14c9ddd6b493eba8a52b523b1ef56ddcff9 100644 (file)
--- a/m4/cppflags.m4
+++ b/m4/cppflags.m4
@@ -23,6 +23,9 @@ AC_DEFUN([NMH_ADDL_CPPFLAGS],
     AC_LANG_WERROR
 
     nmh_saved_cppflags="$CPPFLAGS"
+    dnl autoconf doesn't look at AM_CFLAGS, so merge it into CFLAGS.
+    nmh_saved_cflags="$CFLAGS"
+    CFLAGS="$AM_CFLAGS $CFLAGS"
     dnl On successful compilation, break out of loop with the AM_CPPFLAGS.
     for nmh_cv_addl_cppflags in "" "-D_GNU_SOURCE"; do
         dnl Reload initial CPPFLAGS so candidates aren't accumulated.
@@ -40,8 +43,10 @@ AC_DEFUN([NMH_ADDL_CPPFLAGS],
                   [AC_LANG_PROGRAM([#include <string.h>],
                                    [return strdup("x") == 0])],
                   [AM_CPPFLAGS="${nmh_cv_addl_cppflags}"; break;])])
-    done])
+    done
+    CFLAGS="$nmh_saved_cflags"
     CPPFLAGS="$nmh_saved_cppflags"
+    ])
 
     dnl autoconf doesn't currently provide a macro to disable AC_LANG_WERROR,
     dnl so do it this way: