as an extension, have putenv("VAR") behave as unsetenv("VAR")
[musl] / src / ldso /
drwxr-xr-x   ..
drwxr-xr-x - arm
-rw-r--r-- 146 dladdr.c
-rw-r--r-- 174 dlsym.c
-rw-r--r-- 32005 dynlink.c
drwxr-xr-x - i386
drwxr-xr-x - microblaze
drwxr-xr-x - mips
-rw-r--r-- 105 start.c
drwxr-xr-x - x86_64