https://bugs.gentoo.org/919179
https://src.fedoraproject.org/rpms/perl-Tk/raw/rawhide/f/perl-Tk-c99.patch
https://github.com/eserte/perl-tk/pull/91
--- a/config/unsigned.c
+++ b/config/unsigned.c
@@ -1,15 +1,16 @@
+#include <stdio.h>
 int main()
 {
  char x[] = "\377";
  if (x[0] > 0)
   {
    printf("char is unsigned type\n");
-   exit(0);
+   return 0;
   }
  else
   {
    printf("char is signed type\n");
-   exit(1);
+   return 1;
   }
 }
 
--- a/pTk/config/Hstrdup.c
+++ b/pTk/config/Hstrdup.c
@@ -7,7 +7,7 @@ int main()
 {char *e;
  char *p = strdup(STRING);
  if (!p || strcmp(p,STRING))
-  exit(1);
+  return 1;
  return 0;
 }
 
--- a/pTk/mTk/generic/tkEvent.c
+++ b/pTk/mTk/generic/tkEvent.c
@@ -1153,6 +1153,7 @@ TkEventDeadWindow(winPtr)
 Time
 TkCurrentTime(dispPtr, fallbackCurrent)
     TkDisplay *dispPtr;		/* Display for which the time is desired. */
+    int fallbackCurrent;
 {
     register XEvent *eventPtr;
     ThreadSpecificData *tsdPtr = (ThreadSpecificData *)
--- a/pTk/mTk/generic/tkImage.c
+++ b/pTk/mTk/generic/tkImage.c
@@ -1083,6 +1083,8 @@ int x;
 int y;
 int width;
 int height;
+int imgWidth;
+int imgHeight;
 {
     Tk_Tile tile = (Tk_Tile) clientData;
     Tk_TileChange *handler;