configure has an old ac_cv_header_stdc fragment that calls an undeclared exit function instead of returning from main. Last upstream release apparently was in 2003, even though the web page is still up (without an apparent contact address). So this needs to be fixed in a downstream patch.
Patch looks like this. This is generic autoconf-generated code, fixed in later versions. Other packages will likely need that as well. diff --git a/configure b/configure index 6d93d976873e878e..ed02d3f7fe44d2ab 100755 --- a/configure +++ b/configure @@ -747,8 +747,8 @@ else #define TOUPPER(c) (ISLOWER(c) ? 'A' + ((c) - 'a') : (c)) #define XOR(e, f) (((e) && !(f)) || (!(e) && (f))) int main () { int i; for (i = 0; i < 256; i++) -if (XOR (islower (i), ISLOWER (i)) || toupper (i) != TOUPPER (i)) exit(2); -exit (0); } +if (XOR (islower (i), ISLOWER (i)) || toupper (i) != TOUPPER (i)) return 2; +return 0; } EOF if { (eval echo configure:753: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext} && (./conftest; exit) 2>/dev/null
Created attachment 2007366 [details] tcl-signal-c99-2.patch More fixes are needed for GCC 14 compatibility.