diff --git a/acinclude.m4 b/acinclude.m4
index 1b1e512e9..9c20202d5 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -566,6 +566,7 @@ AC_DEFUN([GB_CHECK_MATH_FUNC],
   [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
       #define _ISOC9X_SOURCE	1
       #define _ISOC99_SOURCE	1
+      #define _GNU_SOURCE	1
       #define __USE_ISOC99	1
       #define __USE_ISOC9X	1
       #include <math.h>
diff --git a/gb.httpd/configure.ac b/gb.httpd/configure.ac
index 9e2145df7..07282dbd2 100644
--- a/gb.httpd/configure.ac
+++ b/gb.httpd/configure.ac
@@ -28,7 +28,7 @@ dnl
 AC_MSG_CHECKING(how to link static binaries)
 AC_CACHE_VAL(ac_cv_lbl_static_flag,
     ac_cv_lbl_static_flag=unknown
-    echo 'main() {}' > conftest.c
+    echo 'int main() {}' > conftest.c
     if test "$GCC" != yes ; then
 	    trial_flag="-Bstatic"
 	    test=`$CC $trial_flag -o conftest conftest.c 2>&1`
@@ -53,7 +53,8 @@ fi
 
 AC_MSG_CHECKING(for __progname)
 AC_CACHE_VAL(ac_cv_extern__progname,
-    AC_LINK_IFELSE([AC_LANG_PROGRAM([[]], [[extern char *__progname; 
+    AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <stdio.h>]],
+        [[extern char *__progname;
 	puts(__progname)]])],[ac_cv_extern__progname=yes],[ac_cv_extern__progname=no]))
 if test $ac_cv_extern__progname = yes ; then
 	AC_DEFINE([HAVE__PROGNAME], [], [have __progname])