./configure --enable-frame-pointers fails if CC contains an absolute path

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For example:

$ CC=/opt/x86_64-linux-musl-native/bin/gcc ./configure --enable-frame-pointers
configure: Configuring OCaml version 4.13.1
checking build system type... x86_64-pc-linux-gnu
checking host system type... x86_64-pc-linux-gnu
checking target system type... x86_64-pc-linux-gnu
checking for ld... ld
checking how to print strings... printf
checking for gcc... /opt/x86_64-linux-musl-native/bin/gcc
checking whether the C compiler works... yes
…
checking for sigwait... yes
checking whether the assembler supports --debug-prefix-map... yes
checking whether the assembler supports CFI directives... yes
configure: error: frame pointers not supported on this platform

I believe this configure script is at fault, which should check for CC containing "gcc", not starting with it (as is done in other places, although not everywhere).