Spurious build warnings

[daira]

configure.ac:28: warning: The macro `AC_PROG_CC_C99' is obsolete.
configure.ac:28: You should run autoupdate.
./lib/autoconf/c.m4:1659: AC_PROG_CC_C99 is expanded from...
configure.ac:28: the top level
[...]
configure.ac:594: warning: $as_echo is obsolete; use AS_ECHO(["message"]) instead
lib/m4sugar/m4sh.m4:692: _AS_IF_ELSE is expanded from...
lib/m4sugar/m4sh.m4:699: AS_IF is expanded from...
./lib/autoconf/general.m4:2249: AC_CACHE_VAL is expanded from...
./lib/autoconf/general.m4:2270: AC_CACHE_CHECK is expanded from...
build-aux/m4/ax_pthread.m4:88: AX_PTHREAD is expanded from...
configure.ac:594: the top level
[...]
Makefile.am:18: warning: user variable 'GZIP_ENV' defined here ...
/usr/share/automake-1.16/am/distdir.am: ... overrides Automake variable 'GZIP_ENV' defined here
[...]
src/Makefile.am:673: warning: variable 'libzcash_a_LDFLAGS' is defined but no program or
src/Makefile.am:673: library has 'libzcash_a' as canonical name (possible typo)
[...]
checking if the linker (/usr/bin/ld -m elf_x86_64) is GNU ld... yes
checking whether the [...]/zcash.pristine/depends/x86_64-pc-linux-gnu/native/bin/clang++ -target x86_64-pc-linux-gnu -B[...]/zcash.pristine/depends/x86_64-pc-linux-gnu/native/bin -stdlib=libc++ -m64 -std=c++17 linker (/usr/bin/ld -m elf_x86_64) supports shared libraries... yes
/usr/bin/grep: warning: stray \ before -
checking for [...]/zcash.pristine/depends/x86_64-pc-linux-gnu/native/bin/clang++ -target x86_64-pc-linux-gnu -B[...]/zcash.pristine/depends/x86_64-pc-linux-gnu/native/bin -stdlib=libc++ -m64 -std=c++17 option to produce PIC... -fPIC -DPIC

[araujo88]

Hello. I'm new as a contributor to zcash and I would like to work on this issue.

[daira]

Thanks, no-one else is working on this so feel free to take it on.

One thing to bear in mind is that some of the files involved are generated via multiple steps. After a build, you can run zcutil/distclean.sh to delete all of the generated files.

[asdfzxh8]

[spam]