selftests, x86: fix how check_cc.sh is being invoked

The $(CC) variable used in Makefiles could contain several arguments
such as "ccache gcc". These need to be passed as a single string to
check_cc.sh, otherwise only the first argument will be used as the
compiler command. Without quotes, the $(CC) variable is passed as
distinct arguments which causes the script to fail to build trivial
programs.

Fix this by adding quotes around $(CC) when calling check_cc.sh to pass
the whole string as a single argument to the script even if it has
several words such as "ccache gcc".

Link: https://lkml.kernel.org/r/d0d460d7[e-mail]
Fixes: e9886ace222e ("selftests, x86: Rework x86 target architecture detection")
Signed-off-by: Guillaume Tucker <[e-mail]>
Tested-by: "kernelci.org bot" <[e-mail]>
Reviewed-by: Guenter Roeck <[e-mail]>
Cc: Shuah Khan <[e-mail]>
Cc: Borislav Petkov <[e-mail]>
Cc: Dave Hansen <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

tools/testing/selftests/vm/Makefile

···
 TEST_GEN_FILES += ksm_tests
 
 ifeq ($(MACHINE),x86_64)
-CAN_BUILD_I386 := $(shell ./../x86/check_cc.sh $(CC) ../x86/trivial_32bit_program.c -m32)
-CAN_BUILD_X86_64 := $(shell ./../x86/check_cc.sh $(CC) ../x86/trivial_64bit_program.c)
-CAN_BUILD_WITH_NOPIE := $(shell ./../x86/check_cc.sh $(CC) ../x86/trivial_program.c -no-pie)
+CAN_BUILD_I386 := $(shell ./../x86/check_cc.sh "$(CC)" ../x86/trivial_32bit_program.c -m32)
+CAN_BUILD_X86_64 := $(shell ./../x86/check_cc.sh "$(CC)" ../x86/trivial_64bit_program.c)
+CAN_BUILD_WITH_NOPIE := $(shell ./../x86/check_cc.sh "$(CC)" ../x86/trivial_program.c -no-pie)
 
 TARGETS := protection_keys
 BINARIES_32 := $(TARGETS:%=%_32)

tools/testing/selftests/x86/Makefile

···
 .PHONY: all all_32 all_64 warn_32bit_failure clean
 
 UNAME_M := $(shell uname -m)
-CAN_BUILD_I386 := $(shell ./check_cc.sh $(CC) trivial_32bit_program.c -m32)
-CAN_BUILD_X86_64 := $(shell ./check_cc.sh $(CC) trivial_64bit_program.c)
-CAN_BUILD_WITH_NOPIE := $(shell ./check_cc.sh $(CC) trivial_program.c -no-pie)
+CAN_BUILD_I386 := $(shell ./check_cc.sh "$(CC)" trivial_32bit_program.c -m32)
+CAN_BUILD_X86_64 := $(shell ./check_cc.sh "$(CC)" trivial_64bit_program.c)
+CAN_BUILD_WITH_NOPIE := $(shell ./check_cc.sh "$(CC)" trivial_program.c -no-pie)
 
 TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs syscall_nt test_mremap_vdso \
 			check_initial_reg_state sigreturn iopl ioperm \