devel/bullet: fix build on powerpc

: && /usr/bin/c++ -fPIC -O2 -pipe -fstack-protector-strong -fno-strict-aliasing -std=c++11 -fopenmp -O2 -pipe -fstack-protector-strong -fno-strict-aliasing  -fstack-protector-strong -shared -Wl,-soname,libHACD.so.3.20 -o Extras/HACD/libHACD.so.3.20 Extras/HACD/CMakeFiles/HACD.dir/hacdGraph.o Extras/HACD/CMakeFiles/HACD.dir/hacdHACD.o Extras/HACD/CMakeFiles/HACD.dir/hacdICHull.o Extras/HACD/CMakeFiles/HACD.dir/hacdManifoldMesh.o  -pthread && :
ld: error: unable to find library -lomp

devel/bullet/Makefile

@@ -30,7 +30,7 @@ GH_PROJECT=	bullet3
 
 CMAKE_ON=	BUILD_BULLET3 BUILD_SHARED_LIBS INSTALL_LIBS \
 		BUILD_EXTRAS INSTALL_EXTRA_LIBS \
-		BULLET2_MULTITHREADING BULLET2_USE_OPEN_MP_MULTITHREADING
+		BULLET2_MULTITHREADING
 CMAKE_OFF=	BUILD_CPU_DEMOS BUILD_BULLET2_DEMOS BUILD_BULLET3_DEMOS \
 		BUILD_OPENGL3_DEMOS BUILD_PYBULLET BUILD_UNIT_TESTS \
 		BULLET2_USE_TBB_MULTITHREADING ENABLE_VHACD \
@@ -51,6 +51,14 @@ OPTIONS_DEFINE=	DOCS
 
 PLIST_SUB=	LIB_VERSION=3.20
 
+.include <bsd.port.options.mk>
+
+.if ${ARCH} == powerpc
+CMAKE_OFF+=	BULLET2_USE_OPEN_MP_MULTITHREADING
+.else
+CMAKE_ON+=	BULLET2_USE_OPEN_MP_MULTITHREADING
+.endif
+
 post-patch:
 	@${RM} -r ${WRKSRC}/examples/pybullet