meson: Update minimum version to 0.57.0

Required for c++20 suppport.

Change-Id: Ida3bdf9615505f7fcc360f5dd246fda5066d6ba5
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/example/meson.build b/example/meson.build
index b437a7d..de1cc6b 100644
--- a/example/meson.build
+++ b/example/meson.build
@@ -5,5 +5,5 @@
 foreach example : examples
   executable(example, example + '.cpp',
              implicit_include_directories: false,
-             dependencies: gpioplus)
+             dependencies: gpioplus_dep)
 endforeach
diff --git a/meson.build b/meson.build
index da5b938..dfb9658 100644
--- a/meson.build
+++ b/meson.build
@@ -1,7 +1,7 @@
 project(
   'gpioplus',
   'cpp',
-  version: '0.1', meson_version: '>=0.53.2',
+  version: '0.1', meson_version: '>=0.57.0',
   default_options: [
     'warning_level=3',
     'cpp_std=c++17',
diff --git a/src/meson.build b/src/meson.build
index b86ed9d..c6fc4ab 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -14,16 +14,15 @@
   version: meson.project_version(),
   install: true)
 
-gpioplus = declare_dependency(
+gpioplus_dep = declare_dependency(
   include_directories: gpioplus_headers,
   link_with: gpioplus_lib,
 )
 
 import('pkgconfig').generate(
-  name: 'gpioplus',
+  gpioplus_lib,
   description: 'C++ systemd event wrapper',
-  version: meson.project_version(),
-  libraries: gpioplus)
+  version: meson.project_version())
 
 install_headers(
   'gpioplus/chip.hpp',
diff --git a/test/meson.build b/test/meson.build
index fbb8e01..f358414 100644
--- a/test/meson.build
+++ b/test/meson.build
@@ -1,20 +1,20 @@
-gtest = dependency('gtest', main: true, disabler: true, required: false)
-gmock = dependency('gmock', disabler: true, required: false)
-if not gtest.found() or not gmock.found()
+gtest_dep = dependency('gtest', main: true, disabler: true, required: false)
+gmock_dep = dependency('gmock', disabler: true, required: false)
+if not gtest_dep.found() or not gmock_dep.found()
+  gtest_opts = import('cmake').subproject_options()
+  gtest_opts.add_cmake_defines({'CMAKE_CXX_FLAGS': '-Wno-pedantic'})
   gtest_proj = import('cmake').subproject(
     'googletest',
-    cmake_options: [
-      '-DCMAKE_CXX_FLAGS=-Wno-pedantic',
-    ],
+    options: gtest_opts,
     required: false)
   if gtest_proj.found()
-    gtest = declare_dependency(
+    gtest_dep = declare_dependency(
       dependencies: [
         dependency('threads'),
         gtest_proj.dependency('gtest'),
         gtest_proj.dependency('gtest_main'),
       ])
-    gmock = gtest_proj.dependency('gmock')
+    gmock_dep = gtest_proj.dependency('gmock')
   else
     assert(not build_tests.enabled(), 'Googletest is required')
   endif
@@ -31,7 +31,10 @@
 ]
 
 foreach t : tests
-  test(t, executable(t.underscorify(), t + '.cpp',
-                     implicit_include_directories: false,
-                     dependencies: [gpioplus, gtest, gmock]))
+  test(
+    t,
+    executable(
+      t.underscorify(), t + '.cpp',
+      implicit_include_directories: false,
+      dependencies: [gpioplus_dep, gtest_dep, gmock_dep]))
 endforeach