X-Git-Url: https://review.openocd.org/gitweb?p=openocd.git;a=blobdiff_plain;f=configure.in;h=07203e137c1efa7643daa3c950d6028c53869c60;hp=3b1d49e4f2bed99888f8181ed20318ca4b558dd1;hb=b227b5eb762f86725d711fb84d665190622e9adc;hpb=caf14c53db57b48303a8f5f3f001faaf0e117f9d

diff --git a/configure.in b/configure.in
index 3b1d49e4f2..07203e137c 100644
--- a/configure.in
+++ b/configure.in
@@ -781,9 +781,41 @@ AM_CONDITIONAL(BITQ, test $build_bitq = yes)
 
 AC_LANG_C
 AC_PROG_CC
+AC_PROG_CC_C99
 AM_PROG_CC_C_O
 AC_PROG_RANLIB
 
+# Look for environ alternatives.  Possibility #1: is environ in unistd.h?
+AC_MSG_CHECKING([for environ in unistd.h])
+AC_COMPILE_IFELSE([
+#define _GNU_SOURCE
+#include <unistd.h>
+int main(int argc, char **argv) { char **ep = environ; }
+  ], [
+    AC_MSG_RESULT([yes])
+    has_environ=yes
+  ], [
+    AC_MSG_RESULT([no])
+
+    # Possibility #2: can environ be found in an available library?
+    AC_MSG_CHECKING([for extern environ])
+    AC_LINK_IFELSE([
+extern char **environ;
+int main(int argc, char **argv) { char **ep = environ; }
+      ], [
+        AC_DEFINE(NEED_ENVIRON_EXTERN, [1], [Must declare 'environ' to use it.])
+        has_environ=yes
+      ], [
+        has_environ=no
+      ])
+    AC_MSG_RESULT([${has_environ}])
+  ])
+
+if test "${has_environ}" != "yes" ; then
+     AC_MSG_FAILURE([Could not find 'environ' in unistd.h or available libraries.]) 
+fi
+
+
 # set default gcc warnings
 GCC_WARNINGS="-Wall -Wstrict-prototypes -Wformat-security"
 if test "${gcc_wextra}" = yes; then