Fails to build on Alpine Linux (musl libc)

[ssssam]

Hi!
I want to use libeatmydata 105 on Alpine Linux. I tried building it and hit the following compile error:

   CC       libeatmydata/libeatmydata_la-libeatmydata.lo
In file included from libeatmydata/libeatmydata.c:25:
libeatmydata/libeatmydata.c:161:22: error: redefinition of 'open'
  161 | int LIBEATMYDATA_API open64(const char* pathname, int flags, ...)
      |                      ^~~~~~
/usr/include/fcntl.h:34:5: note: previous definition of 'open' was here
   34 | int open(const char *, int, ...);
      |     ^~~~
make: *** [Makefile:1043: libeatmydata/libeatmydata_la-libeatmydata.lo] Error 1

This is most likely due to differences between GLIBC and musl libc. I wonder if musl is doing #define open64 open or something like that?

The full build log is here.

[ssssam]

Musl is indeed doing this in fcntl.h:

fcntl.h:#define open64 open

I've managed to build libeatmydata from df7ddeb by adding this workaround to the build process:

sed -e 's/^#define HAVE_OPEN64 /#undef HAVE_OPEN64/' -i config.h

I also tried adding this to the .c code before open64() is defined:

#undef open64

It seems to work both on Alpine Linux (musl) and Fedora 31 (glibc). So i've opened #18