dia: fix musl build (alpine patch)

srcpkgs/dia/patches/isinf.patch

@@ -0,0 +1,16 @@
+--- ./configure.orig
++++ ./configure
+@@ -17436,11 +17436,11 @@
+ #ifdef __cplusplus
+ extern "C"
+ #endif
+-char isinf ();
++#include <math.h>
+ int
+ main ()
+ {
+-return isinf ();
++return isinf (0.0);
+   ;
+   return 0;
+ }