configure: add macro to check for __PROGNAME

in include/c.h we check if HAVE___PROGNAME is defined, but the
corresponding macro for setting (or not setting) it is missing from
the configure script. This commit adds the missing macro, by
copying it from the macro in tmux.

diff --git a/configure.ac b/configure.ac
index 3e83fb88330c6f5f33528714348da9575c0e3a16..659e57b59872b16ec88a04eb08ecb0749303eac3 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -116,6 +116,22 @@ AC_CHECK_HEADERS(error.h, [], [], AC_INCLUDES_DEFAULT)
 
 AC_CHECK_HEADERS(stdio_ext.h, [], [], AC_INCLUDES_DEFAULT)
 
+AC_MSG_CHECKING(for __progname)
+AC_LINK_IFELSE([AC_LANG_SOURCE(
+       [
+               #include <stdio.h>
+               #include <stdlib.h>
+               extern char *__progname;
+               int main(void) {
+                       const char *cp = __progname;
+                       printf("%s\n", cp);
+                       exit(0);
+               }
+       ])],
+       AC_DEFINE(HAVE___PROGNAME, 1, [Define if __progname exists])
+       AC_MSG_RESULT(yes),
+       AC_MSG_RESULT(no))
+
 AC_MSG_CHECKING(whether program_invocation_name is defined)
 AC_TRY_COMPILE([#include <errno.h>],
                [program_invocation_name = "test";],