+++ /dev/null
-diff --git a/libpcc/bitcnt.c b/libpcc/bitcnt.c
-index 26ecc01..c3bd54e 100644
---- a/libpcc/bitcnt.c
-+++ b/libpcc/bitcnt.c
-@@ -1,9 +1,22 @@
-+// Only use __has_builtin in compilers that support it.
-+#ifndef __has_builtin
-+ #define __has_builtin(x) 0
-+#endif
-
-+#if !__has_builtin(__builtin_clz)
- int __builtin_clz(unsigned int);
-+#endif
-+#if !__has_builtin(__builtin_ctz)
- int __builtin_ctz(unsigned int);
-+#endif
-+#if !__has_builtin(__builtin_clzl)
- int __builtin_clzl(unsigned long);
-+#endif
-+#if !__has_builtin(__builtin_ctzl)
- int __builtin_ctzl(unsigned long);
-+#endif
-
-+#if !__has_builtin(__builtin_clz)
- int
- __builtin_clz(unsigned int v)
- {
-@@ -14,7 +27,9 @@ __builtin_clz(unsigned int v)
- break;
- return i;
- }
-+#endif
-
-+#if !__has_builtin(__builtin_ctz)
- int
- __builtin_ctz(unsigned int v)
- {
-@@ -25,7 +40,9 @@ __builtin_ctz(unsigned int v)
- break;
- return i;
- }
-+#endif
-
-+#if !__has_builtin(__builtin_clzl)
- int
- __builtin_clzl(unsigned long v)
- {
-@@ -37,7 +54,9 @@ __builtin_clzl(unsigned long v)
- break;
- return i;
- }
-+#endif
-
-+#if !__has_builtin(__builtin_ctzl)
- int
- __builtin_ctzl(unsigned long v)
- {
-@@ -48,3 +67,4 @@ __builtin_ctzl(unsigned long v)
- break;
- return i;
- }
-+#endif