OpenBLAS: disable USE_OPENMP when building on a single core machine.

component/openblas/buildout.cfg

@@ -9,6 +9,9 @@ extends =
 recipe = slapos.recipe.cmmi
 url = http://github.com/xianyi/OpenBLAS/archive/v0.2.15.tar.gz
 md5sum = b1190f3d3471685f17cfd1ec1d252ac9
+patch-options = -p0
+patches =
+  ${:_profile_base_location_}/disable_openmp_if_single_core.patch#ee553ccaf9dd4bc37374588e49956f62
 
 build-common-options = BINARY="$(uname -m | grep -q x86_64 && echo 64 || echo 32)" NO_STATIC=1 USE_OPENMP=1 USE_THREAD=1
 

component/openblas/disable_openmp_if_single_core.patch

+diff --git Makefile.system Makefile.system
+index 42ad498..d43aa7a 100644
+--- Makefile.system
++++ Makefile.system
+@@ -171,6 +171,7 @@ endif
+ 
+ ifeq ($(NUM_THREADS), 1)
+ override USE_THREAD = 0
++override USE_OPENMP = 0
+ endif
+ 
+ ifdef USE_THREAD