https://bugs.gentoo.org/874021
--- a/Configure
+++ b/Configure
@@ -78,3 +78,3 @@
 echo "Checking for libraries"
-echo 'main(){}' > test.c
+echo 'int main(void){return 0;}' > test.c
 LFLAGS=""
@@ -96,4 +96,5 @@
 cat << END > test.c
-void handler(void) {}
-main() { on_exit(handler, (void *)0); }
+#include <stdlib.h>
+void handler(int a, void *b) {}
+int main(void) { on_exit(handler, (void *)0); return 0; }
 END
@@ -108,3 +109,3 @@
 #include <signal.h>
-main() { sigset_t set; sigprocmask(SIG_BLOCK, &set, &set); }
+int main(void) { sigset_t set; sigprocmask(SIG_BLOCK, &set, &set); return 0; }
 END
@@ -119,3 +120,3 @@
 #include <getopt.h>
-main(){}
+int main(void){return 0;}
 END
@@ -131,3 +132,3 @@
 #include <memory.h>
-main(){}
+int main(void){return 0;}
 END