third_party/pffft/patches/01-add_m_pi.diff

diff --git a/third_party/pffft/src/pffft.c b/third_party/pffft/src/pffft.c
index 0603f2b1f698..7934db448a09 100644
--- a/third_party/pffft/src/pffft.c
+++ b/third_party/pffft/src/pffft.c
@@ -82,6 +82,9 @@
 #  define VLA_ARRAY_ON_STACK(type__, varname__, size__) type__ *varname__ = (type__*)_alloca(size__ * sizeof(type__))
 #endif
 
+#ifndef M_PI
+#define M_PI 3.14159265358979323846
+#endif
 
 /* 
    vector support macros: the rest of the code is independant of