Update meson build system.

This commit brings the meson build system branch up-to-date
with the current CMake build system. It should be possible
now to build and test flatcc using the Meson build system, like so:

$ meson setup build
$ meson compile -C build
$ meson test -C build

This is not yet integrated with the shell scripts in the
scipts directory.

meson.build

@@ -0,0 +1,228 @@
+# NOTE: This build system is maintained by the community.
+project('flatcc',
+  'c', 'cpp',
+  version : '0.6.1',
+  license : 'Apache-2.0',
+  default_options : ['c_std=c11', 'cpp_std=c++11', 'default_library=static'],
+  meson_version : '>=0.56.0'
+)
+
+buildtype = get_option('buildtype')
+ignore_const_cond = get_option('ignore_const_cond')
+allow_werror = get_option('allow_werror')
+gnu_posix_memalign = get_option('gnu_posix_memalign')
+has_c99_var_decl = get_option('c_std') != 'c89'
+
+cc = meson.get_compiler('c')
+cc_id = cc.get_id()
+cc_version = cc.version()
+
+cxx = meson.get_compiler('cpp')
+
+c_args = []
+
+if get_option('flatcc_portable') or cc_id == 'msvc'
+  c_args += '-DFLATCC_PORTABLE'
+endif
+
+if get_option('flatcc_debug_verify')
+  c_args += '-DFLATCC_DEBUG_VERIFY=1'
+endif
+
+if get_option('flatcc_fast_double')
+  c_args += '-DGRISU3_PARSE_ALLOW_ERROR'
+  c_args += '-DFLATCC_USE_GRISU3=1'
+endif
+
+if buildtype == 'release' or buildtype == 'minsize'
+  c_args += '-DNDEBUG'
+endif
+
+if cc_id == 'mvsc'
+
+  has_c99_var_decl = cc_version.version_compare('>=18')
+
+elif cc_id == 'clang'
+
+  c_args += [
+    '-Wstrict-prototypes',
+    '-Wsign-conversion',
+    '-Wconversion',
+    '-pedantic',
+    '-Wextra'
+  ]
+
+  if ignore_const_cond
+    c_args += '-Wno-tautological-constant-out-of-range-compare'
+  endif
+
+  if cc_version.version_compare('< 6')
+    c_args += '-Wno-missing-field-initializers'
+  endif
+
+elif cc_id == 'gcc'
+
+  c_args += [
+    '-Wall',
+    '-Wextra',
+  ]
+
+  if ignore_const_cond
+    c_args += '-Wno-type-limits'
+  endif
+
+  if cc_version.version_compare('>4.8')
+    c_args += '-Wsign-compare'
+  endif
+
+  if cc_version.version_compare('>8')
+    c_args += [ '-Wno-stringop-truncation', '-Wno-format-overflow' ]
+  endif
+
+  if cc_version.version_compare('>=11')
+    c_args += '-Wno-misleading-indentation'
+  endif
+
+  if gnu_posix_memalign
+    c_args += '-DPORTABLE_POSIX_MEMALIGN=1'
+  endif
+
+endif
+
+if allow_werror
+ c_args += '-Werror'
+endif
+
+# Reflection must be disabled temporarily when making breaking changes.
+if get_option('flatcc_reflection')
+  c_args += '-DFLATCC_REFLECTION=1'
+else
+  c_args += '-DFLATCC_REFLECTION=0'
+endif
+
+add_project_arguments(cc.get_supported_arguments(c_args), language: 'c')
+add_project_arguments(cxx.get_supported_arguments(c_args), language: 'cpp')
+
+if get_option('xflatcc_gen_version')
+  revisition_tag = vcs_tag(
+    input: 'config/version.in',
+    output: 'revision',
+    command: ['git', 'rev-parse', 'HEAD'],
+    fallback: 'n/a'
+  )
+
+  version_tag = vcs_tag(
+    input: 'config/version.in',
+    output: 'version',
+    command: ['git', 'describe', '--abbrev=0', '--tags'],
+    fallback: 'n/a'
+  )
+endif
+
+inc_dir = include_directories('include', 'config', 'external')
+
+if not meson.is_subproject()
+  install_subdir('include/flatcc', install_dir: 'include')
+endif
+
+flatccrt_src = [
+  'src/runtime/builder.c',
+  'src/runtime/emitter.c',
+  'src/runtime/refmap.c',
+  'src/runtime/json_parser.c',
+  'src/runtime/json_printer.c',
+  'src/runtime/verifier.c'
+]
+
+flatcc_src = [
+  'src/compiler/codegen_c.c',
+  'src/compiler/codegen_c_builder.c',
+  'src/compiler/codegen_c_json_parser.c',
+  'src/compiler/codegen_c_json_printer.c',
+  'src/compiler/codegen_c_reader.c',
+  'src/compiler/codegen_c_sort.c',
+  'src/compiler/codegen_c_sorter.c',
+  'src/compiler/codegen_c_verifier.c',
+  'src/compiler/codegen_schema.c',
+  'src/compiler/coerce.c',
+  'src/compiler/fileio.c',
+  'src/compiler/flatcc.c',
+  'src/compiler/parser.c',
+  'src/compiler/semantics.c',
+  'src/compiler/hash_tables/name_table.c',
+  'src/compiler/hash_tables/schema_table.c',
+  'src/compiler/hash_tables/scope_table.c',
+  'src/compiler/hash_tables/symbol_table.c',
+  'src/compiler/hash_tables/value_set.c',
+  'external/hash/cmetrohash64.c',
+  'external/hash/ptr_set.c',
+  'external/hash/str_set.c',
+  flatccrt_src
+]
+
+flatccrt_name = 'flatccrt'
+flatcc_name = 'flatcc'
+
+if buildtype == 'debug'
+  flatccrt_name = 'flatccrt_d'
+  flatcc_name = 'flatcc_d'
+endif
+
+
+libflatccrt = library(flatccrt_name,
+  sources: flatccrt_src,
+  include_directories: inc_dir,
+  install: not meson.is_subproject()
+)
+
+libflatcc = library(flatcc_name,
+  sources: flatcc_src,
+  include_directories: inc_dir,
+  install: not meson.is_subproject()
+)
+
+flatcc = executable(flatcc_name,
+  sources: ['src/cli/flatcc_cli.c'],
+  link_with: libflatcc,
+  include_directories: inc_dir,
+  install: not meson.is_subproject()
+)
+
+if not meson.is_subproject()
+
+  mkdir_command = find_program('mkdir')
+  cp_command = find_program('cp')
+
+  copy_targets = {
+    'flatcc-copy' : [flatcc, meson.project_source_root() / 'bin'],
+    'libflatccrt-copy' : [libflatccrt, meson.project_source_root() / 'lib'],
+    'libflatcc-copy' : [libflatcc, meson.project_source_root() / 'lib']
+  }
+
+  foreach target_name, target_details : copy_targets
+    target = target_details[0]
+    destination = target_details[1]
+    custom_target(target_name,
+      command: [ mkdir_command, '-p', destination, '&&', cp_command, target, destination ],
+      output: 'fake-@0@'.format(target_name),
+      build_by_default: true,
+      build_always_stale: false
+    )
+  endforeach
+endif
+
+meson.override_find_program('flatcc', flatcc)
+
+subdir('rules')
+
+if not get_option('flatcc_disable_tests') and not meson.is_subproject()
+  # For end user programs, samples, and test.
+  subdir('samples')
+  subdir('test')
+endif
+
+flatcc_dep = declare_dependency(
+  link_with: libflatcc,
+  include_directories: inc_dir
+)
+

meson_options.txt

@@ -0,0 +1,78 @@
+# Use this for some compilers that doesn't C11 standard.
+# It is not needed for some non-compliant compilers such as
+# recent gcc and clang.
+
+option('flatcc_portable', type : 'boolean', value : false)
+
+# Use this option to trigger assertions on flatcc errors. Useful to
+# learn more about why api is used incorrectly or where a binary
+# flatbuffer fails a verify test.
+
+option('flatcc_debug_verify', type : 'boolean', value : false)
+
+# Controls the flatcc compilers ability to handle binary schema (bfbs).
+# Can be used to trim down flatcc and libflatcc size, but is primarily
+# for internal development because flatcc won't otherwise compile while
+# there are breaking changes in generated code.
+
+option('flatcc_reflection', type : 'boolean', value : true)
+
+# This option controls a special case in grisu3 but does not enable or
+# disable grisu3 floating point parsing, which is enabled without
+# special configuration elsewhere:
+#
+# Fast grisu3 string/floating point conversion still depends on strtod
+# for about 1-2% of the conversions in order to produce an exact result.
+# By allowing a minor difference in the least significant bits, this
+# dependeny can be avoided, and speed improved. Some strtod
+# implementations call strlen which is really slow on large JSON
+# buffers, and catastrophic on buffers that are not zero-terminated -
+# regardless of size. Most platforms have a decent strtod these days.
+
+option('flatcc_fast_double', type : 'boolean', value : false)
+
+# Only build libraries, not samples, tests, or benchmarks.
+# This option is implied true when building as a subproject
+# regardless of this setting.
+
+option('flatcc_disable_tests', type : 'boolean', value : false)
+
+option('ignore_const_cond', type: 'boolean', value: false)
+option('allow_werror', type: 'boolean', value: true)
+option('gnu_posix_memalign', type: 'boolean', value: true) 
+
+# --
+# -- For more detailed control, see also config/config.h compiler flags.
+# --
+
+
+#####################################################################
+#
+# EXPERIMENTAL SETTINGS
+#
+# Subject to change without notice.
+#
+#####################################################################
+
+
+# dealing with missing support for proper multi output dependencies in
+# both ninja build and in flatcc. For now the myschema_reader.h is used
+# to drive the depencies.
+
+option('xflatcc_multi_dep_targets', type : 'boolean', value : false)
+
+# Removes all tests, except the important `monster_test`.
+# Useful for smaller test suite on new build targets
+# and for testing dependency rules without noise.
+
+option('xflatcc_monster_test_only', type : 'boolean', value : false)
+
+# Currently (meson 0.34) it is not possible to generate .bfbs. files
+# because there must be a registered compiler that handles .bfbs
+# extension, but it is possible to use a custom target that does.
+
+option('xflatcc_reflection_test_custom', type : 'boolean', value : true)
+
+# Experimental support for automatically generating latest tag
+# and revision from source control.
+option('xflatcc_gen_version', type : 'boolean', value : false)