diff --git a/backends/aiger/xaiger.cc b/backends/aiger/xaiger.cc
index 69f63486c..6aa9cde54 100644
--- a/backends/aiger/xaiger.cc
+++ b/backends/aiger/xaiger.cc
@@ -53,7 +53,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 inline int32_t to_big_endian(int32_t i32) {
 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
-	return __builtin_bswap32(i32);
+	return bswap32(i32);
 #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
 	return i32;
 #else
diff --git a/passes/techmap/abc.cc b/passes/techmap/abc.cc
index 65c7d1bb8..19afb58cb 100644
--- a/passes/techmap/abc.cc
+++ b/passes/techmap/abc.cc
@@ -49,6 +49,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
+#include <cctype>
 #include <cerrno>
 #include <sstream>
 #include <climits>