[PATCH v2] Add more checks for headers and libraries in the meson build

[Tulio Magno Quites Machado Filho]

From: Tulio Magno Quites Machado Filho <tuliom@redhat.com>

Changes since v1:
 - Dropped changes from annocheck.

--- 8< ---

gcc-plugin depends on plugin.h.
clang-plugin depends on libraries clang-cpp and LLVM.
llvm-plugin depends on library LLVM.
---
 clang-plugin/meson.build |  5 +++++
 gcc-plugin/meson.build   | 19 ++++++++++++++++++-
 llvm-plugin/meson.build  |  4 ++++
 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/clang-plugin/meson.build b/clang-plugin/meson.build
index 0c415db..5240a76 100644
--- a/clang-plugin/meson.build
+++ b/clang-plugin/meson.build
@@ -6,6 +6,11 @@ clang = find_program('clang++')
 search_dirs = run_command(clang , '--print-search-dirs', check: true).stdout().strip()
 install_dir = search_dirs.split('\n')[1].split(':')[1].replace('=', '').strip()
 
+# Use the default c++ compiler just to find if the needed libraries are
+# installed.
+cxx.find_library('LLVM')
+cxx.find_library('clang-cpp')
+
 clang_plugin = custom_target(
   'annobin-for-clang.so',
   input: 'annobin.cpp',
diff --git a/gcc-plugin/meson.build b/gcc-plugin/meson.build
index e0ee998..b234369 100644
--- a/gcc-plugin/meson.build
+++ b/gcc-plugin/meson.build
@@ -55,6 +55,23 @@ endif
 # using GCC, even if the environment wants another compiler.
 gxx = find_program('g++')
 plugin_dev_path = run_command(gxx, '-print-file-name=plugin', check: true).stdout().strip()
+
+# Use the default c++ compiler just to find if the needed dependencies are
+# installed.
+plugin_inc_path = join_paths(plugin_dev_path, 'include')
+fs = import('fs')
+if not fs.is_dir(plugin_inc_path)
+  error(
+    'Could not find ',
+    plugin_inc_path,
+    '\nAre the development files for GCC plugins installed?',
+  )
+endif
+inc = include_directories(plugin_inc_path)
+if not cxx.has_header('plugin.h', include_directories: inc)
+  error('Could not find GCC\'s plugin.h')
+endif
+
 gcc_plugin = custom_target(
   'annobin.so',
   input: ['annobin.cc', target_plugin],
@@ -68,7 +85,7 @@ gcc_plugin = custom_target(
     '-DHAVE_CONFIG_H',
     '-I' + join_paths(meson.current_source_dir(), '..'),
     '-I' + join_paths(meson.current_build_dir(), '..'),
-    '-I' + join_paths(plugin_dev_path, 'include'),
+    '-I' + join_paths(plugin_inc_path),
     '-o', '@OUTPUT@',
   ]
 )
diff --git a/llvm-plugin/meson.build b/llvm-plugin/meson.build
index 17930b3..317f046 100644
--- a/llvm-plugin/meson.build
+++ b/llvm-plugin/meson.build
@@ -6,6 +6,10 @@ clang = find_program('clang++')
 search_dirs = run_command(clang , '--print-search-dirs', check: true).stdout().strip()
 install_dir = search_dirs.split('\n')[1].split(':')[1].replace('=', '').strip()
 
+# Use the default c++ compiler just to find if the needed libraries are
+# installed.
+cxx.find_library('LLVM')
+
 llvm_plugin = custom_target(
   'annobin-for-llvm.so',
   input: 'annobin.cpp',
-- 
2.49.0