Makefile.arm: remove -march flags

The provided -march flags, especially for ARMv5 and ARMv6 may not
necessarily match the needed ones: for ARMv5, it might be armv5,
armv5te, armv5t, etc. If the wrong one is used, the incorrect toolchain
sysroot can be used in a multilib toolchain.

Therefore, let the user building OpenBLAS pass the appropriate -march
flag.

The other flags, such as -mfpu=vfp or -mfloat-abi=hard are kept, as they
are actually required for the build to proceed (OpenBLAS uses VFP
instructions, and assume an EABIhf ABI).

[Peter: update for v0.2.20]
Signed-off-by: Thomas Petazzoni <[email protected]>
Signed-off-by: Peter Korsgaard <[email protected]>
[Retrieved from:
https://git.buildroot.net/buildroot/tree/package/openblas/0001-Makefile.arm-remove-march-flags.patch]
Signed-off-by: Fabrice Fontaine <[email protected]>

Author: ffontaine

Makefile.arm

@@ -1,19 +1,14 @@
 ifeq ($(CORE), $(filter $(CORE),ARMV7 CORTEXA9 CORTEXA15))
 ifeq ($(OSNAME), Android)
-CCOMMON_OPT += -mfpu=neon  -march=armv7-a
-FCOMMON_OPT += -mfpu=neon  -march=armv7-a
+CCOMMON_OPT += -mfpu=neon
+FCOMMON_OPT += -mfpu=neon
 else
 CCOMMON_OPT += -mfpu=vfpv3 -march=armv7-a
 FCOMMON_OPT += -mfpu=vfpv3 -march=armv7-a
 endif
 endif
 
 ifeq ($(CORE), ARMV6)
-CCOMMON_OPT += -mfpu=vfp -march=armv6
-FCOMMON_OPT += -mfpu=vfp -march=armv6
-endif
-
-ifeq ($(CORE), ARMV5)
-CCOMMON_OPT += -march=armv5
-FCOMMON_OPT += -march=armv5
+CCOMMON_OPT += -mfpu=vfp
+FCOMMON_OPT += -mfpu=vfp
 endif