arm-unknown-linux-musleabi updates for ARMv6

The arm-unknown-linux-musleabi target used in meta-rust for Yocto didn't
explicitly set the arch to ARMv6 and soft float but was instead done via
target spec files and never had the compiler running on the target.

Author: cardoe

mk/cfg/arm-unknown-linux-musleabi.mk

@@ -8,8 +8,8 @@ CFG_LIB_NAME_arm-unknown-linux-musleabi=lib$(1).so
 CFG_STATIC_LIB_NAME_arm-unknown-linux-musleabi=lib$(1).a
 CFG_LIB_GLOB_arm-unknown-linux-musleabi=lib$(1)-*.so
 CFG_LIB_DSYM_GLOB_arm-unknown-linux-musleabi=lib$(1)-*.dylib.dSYM
-CFG_JEMALLOC_CFLAGS_arm-unknown-linux-musleabi := -D__arm__ $(CFLAGS)
-CFG_GCCISH_CFLAGS_arm-unknown-linux-musleabi := -Wall -g -fPIC -D__arm__ $(CFLAGS)
+CFG_JEMALLOC_CFLAGS_arm-unknown-linux-musleabi := -D__arm__ -mfloat-abi=soft $(CFLAGS) -march=armv6 -marm
+CFG_GCCISH_CFLAGS_arm-unknown-linux-musleabi := -Wall -g -fPIC -D__arm__ -mfloat-abi=soft $(CFLAGS) -march=armv6 -marm
 CFG_GCCISH_CXXFLAGS_arm-unknown-linux-musleabi := -fno-rtti $(CXXFLAGS)
 CFG_GCCISH_LINK_FLAGS_arm-unknown-linux-musleabi := -shared -fPIC -g
 CFG_GCCISH_DEF_FLAG_arm-unknown-linux-musleabi := -Wl,--export-dynamic,--dynamic-list=
@@ -24,6 +24,3 @@ CFG_RUN_TARG_arm-unknown-linux-musleabi=$(call CFG_RUN_arm-unknown-linux-musleab
 RUSTC_FLAGS_arm-unknown-linux-musleabi :=
 RUSTC_CROSS_FLAGS_arm-unknown-linux-musleabi :=
 CFG_GNU_TRIPLE_arm-unknown-linux-musleabi := arm-unknown-linux-musleabi
-# This file is intentially left empty to indicate that, while this target is
-# supported, it's not supported using plain GNU Make builds. Use a --rustbuild
-# instead.