dia: fix configure for c99 and gcc14

srcpkgs/dia/patches/gcc14.patch

@@ -0,0 +1,35 @@
+Source: https://src.fedoraproject.org/rpms/dia/blob/7ebdbadff67fe2ee482d8655fcb3d361b31742f3/f/dia-configure-c99.patch
+
+C99 removes support for implicit ints, so declare the return type
+of main explicitly.  Future compilers are likely to require explicit
+type declarations.
+
+Upstream has switched to Meson, and it does not seem to use this
+particular check anymore.
+
+diff --git a/configure b/configure
+index 14cdc757c3ee0f15..504ae93d8e3a4f48 100755
+--- a/configure
++++ b/configure
+@@ -17571,7 +17571,7 @@ $as_echo_n "checking for png_structp in png.h... " >&6; }
+                   png_structp pp;
+ 		  png_infop info;
+ 		  png_colorp cmap;
+-		  main() { void*foo = png_create_read_struct; }
++		  int main(void) { void*foo = png_create_read_struct; }
+ _ACEOF
+ if ac_fn_c_try_link "$LINENO"; then :
+   png_ok=yes
+diff --git a/configure.in b/configure.in
+index c5edeeddf766d5fb..f90ed4ef953af139 100644
+--- a/configure.in
++++ b/configure.in
+@@ -197,7 +197,7 @@ if test "$png_ok" = yes; then
+                   png_structp pp;
+ 		  png_infop info; 
+ 		  png_colorp cmap; 
+-		  main() { void*foo = png_create_read_struct; }],
++		  int main(void) { void*foo = png_create_read_struct; }],
+                  png_ok=yes,
+                  png_ok=no)
+   LDFLAGS="${old_LDFLAGS}"