lib9: make a p9frexp function wrapping system frexp

Under certain conditions it looks like frexp gets #defined
to something else on macOS during system headers,
which then breaks the declaration in libc.h.

1 files changed, 9 insertions, 0 deletions

diff --git a/src/lib9/frexp.c b/src/lib9/frexp.c
new file mode 100644
index 00000000..fe3e2f73
--- /dev/null
+++ b/src/lib9/frexp.c
@@ -0,0 +1,9 @@
+#include <u.h>
+#define NOPLAN9DEFINES
+#include <libc.h>
+
+double
+p9frexp(double d, int *i)
+{
+	return frexp(d, i);
+}