After changing some && to & in src/wildmidi_lib.c and doing "./bootstrap ; ./configure --disable-optimize ; make", I got this error related to WM_SampleRate being used in both src/gus_pat.c and src/wildmidi_lib.c:

Making all in src
/bin/sh ../libtool --tag=CC --mode=link gcc -std=c99 -U__STRICT_ANSI__ -Wall -Wextra -pedantic -Werror -version-info 2:0:1 -shared -lm -lc -no-undefined -export-symbols-regex '^WildMidi.' -lm -lc -o libWildMidi.la -rpath /usr/local/lib libWildMidi_la-wm_error.lo libWildMidi_la-file_io.lo libWildMidi_la-reverb.lo libWildMidi_la-lock.lo libWildMidi_la-gus_pat.lo libWildMidi_la-wildmidi_lib.lo -lm -lc
libtool: link: rm -fr .libs/libWildMidi.exp
libtool: link: /usr/bin/nm .libs/libWildMidi_la-wm_error.o .libs/libWildMidi_la-file_io.o .libs/libWildMidi_la-reverb.o .libs/libWildMidi_la-lock.o .libs/libWildMidi_la-gus_pat.o .libs/libWildMidi_la-wildmidi_lib.o | sed -n -e 's/^. [ ][ ]__([_A-Za-z][A-Za-z0-9])$/\1 \2 \2/p' | sed '/ _gnu_lto/d' | /usr/bin/sed 's/. //' | sort | uniq > .libs/libWildMidi.exp
libtool: link: /usr/bin/grep -E -e "^WildMidi.*" ".libs/libWildMidi.exp" > ".libs/libWildMidi.expT"
libtool: link: mv -f ".libs/libWildMidi.expT" ".libs/libWildMidi.exp"
libtool: link: sed 's,^,,' < .libs/libWildMidi.exp > .libs/libWildMidi-symbols.expsym
libtool: link: gcc -dynamiclib -o .libs/libWildMidi.1.dylib .libs/libWildMidi_la-wm_error.o .libs/libWildMidi_la-file_io.o .libs/libWildMidi_la-reverb.o .libs/libWildMidi_la-lock.o .libs/libWildMidi_la-gus_pat.o .libs/libWildMidi_la-wildmidi_lib.o -lm -lc -install_name /usr/local/lib/libWildMidi.1.dylib -compatibility_version 3 -current_version 3.0 -Wl,-single_module -Wl,-exported_symbols_list,.libs/libWildMidi-symbols.expsym
duplicate symbol _WM_SampleRate in:
.libs/libWildMidi_la-gus_pat.o
.libs/libWildMidi_la-wildmidi_lib.o
ld: 1 duplicate symbol for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[1]: *** [libWildMidi.la] Error 1
make: *** [all-recursive] Error 1