meson: set the symbol visibility of the shared library to hidden

This matches the Makefile build. Due to one private xxhash symbol in use
by the program, it recompiles a private copy of xxhash.

Ref. #2261

build/meson/lib/meson.build

@@ -108,6 +108,7 @@ libzstd = library('zstd',
   libzstd_sources,
   include_directories: libzstd_includes,
   c_args: libzstd_c_args,
+  gnu_symbol_visibility: 'hidden',
   dependencies: libzstd_deps,
   install: true,
   version: zstd_libversion)

build/meson/meson.build

@@ -19,7 +19,7 @@ project('zstd',
     'werror=true'
   ],
   version: 'DUMMY',
-  meson_version: '>=0.47.0')
+  meson_version: '>=0.48.0')
 
 cc = meson.get_compiler('c')
 cxx = meson.get_compiler('cpp')

build/meson/programs/meson.build

@@ -18,7 +18,9 @@ zstd_programs_sources = [join_paths(zstd_rootdir, 'programs/zstdcli.c'),
   join_paths(zstd_rootdir, 'programs/benchzstd.c'),
   join_paths(zstd_rootdir, 'programs/datagen.c'),
   join_paths(zstd_rootdir, 'programs/dibio.c'),
-  join_paths(zstd_rootdir, 'programs/zstdcli_trace.c')]
+  join_paths(zstd_rootdir, 'programs/zstdcli_trace.c'),
+  # needed due to use of private symbol + -fvisibility=hidden
+  join_paths(zstd_rootdir, 'lib/common/xxhash.c')]
 
 zstd_c_args = libzstd_debug_cflags
 if use_multi_thread