PATH_MAX is not defined unless we pull in <limits.h> on musl.

--- astyle/src/astyle_main.cpp.old	2018-01-11 17:18:19.000000000 +0000
+++ astyle/src/astyle_main.cpp	2020-07-19 20:23:56.774222078 +0000
@@ -37,6 +37,7 @@
 
 #include <algorithm>
 #include <cerrno>
+#include <climits>
 #include <clocale>		// needed by some compilers
 #include <cstdlib>
 #include <fstream>