ifstat: fix compilation with GCC14

Need explicit int.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

net/ifstat/patches/010-gcc14.patch

@@ -0,0 +1,11 @@
+--- a/configure
++++ b/configure
+@@ -783,7 +783,7 @@ cat > conftest.$ac_ext << EOF
+ #line 784 "configure"
+ #include "confdefs.h"
+ 
+-main(){return(0);}
++int main(){return(0);}
+ EOF
+ if { (eval echo configure:789: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext}; then
+   ac_cv_prog_cc_works=yes