Note that in C++ the static keyword is implicit for const objects.
In C however it is not, and we get clashes at link time after
including the header from more than one C file:
lib.a(bar.o):(.rodata+0x0): multiple definition of `__tsan_mutex_linker_init' lib.a(foo.o):(.rodata+0x0): first defined here lib.a(bar.o):(.rodata+0xc): multiple definition of `__tsan_mutex_not_static' lib.a(foo.o):(.rodata+0xc): first defined here <snip>
Indeed both foo.o and bar.o define the clashing symbols:
$ nm foo.o <snip> 0000000000000000 R __tsan_mutex_linker_init 000000000000000c R __tsan_mutex_not_static <snip>
Fix it by explicitly making the constants static.