Fix an implicit declaration of atoi during the non-autoconf configure
stage.  Otherwise these configure probes will not work with future
compilers.

diff --git a/scconfig/src/math/find_mfunc_cc.c b/scconfig/src/math/find_mfunc_cc.c
index 911385a5fa896d9b..54f82f29d6f1868f 100644
--- a/scconfig/src/math/find_mfunc_cc.c
+++ b/scconfig/src/math/find_mfunc_cc.c
@@ -32,6 +32,7 @@
 
 static char *test_c_templ =
 	NL "#include <stdio.h>"
+	NL "#include <stdlib.h>"
 	NL "#include <math.h>"
 	NL "#include <errno.h>"
 	NL "int main(int argc, char *argv[]) {"