xscope 1.4.3 build failure

On macOS, xscope 1.4.3 fails like this:

gcc -DHAVE_CONFIG_H -I.   -I/sw/include -Wall -Wpointer-arith -Wmissing-declarations -Wformat=2 -Wstrict-prototypes -Wmissing-prototypes -Wnested-externs -Wbad-function-cast -Wold-style-definition -Wdeclaration-after-statement -Wunused -Wuninitialized -Wshadow -Wmissing-noreturn -Wmissing-format-attribute -Wredundant-decls -Werror=implicit -Werror=nonnull -Werror=init-self -Werror=main -Werror=missing-braces -Werror=sequence-point -Werror=return-type -Werror=trigraphs -Werror=array-bounds -Werror=write-strings -Werror=address -Werror=int-to-pointer-cast -Werror=pointer-to-int-cast -fno-strict-aliasing -I/sw/opt/X11/include -g -O2 -MT audio.o -MD -MP -MF .deps/audio.Tpo -c -o audio.o audio.c
In file included from audio.c:24:
In file included from ./scope.h:71:
./fd.h:101:27: error: expected function body after function declarator
extern int MainLoop(void) _X_NORETURN;
                          ^
1 error generated.

This is related to !5 (merged)