[mm-common] skeletonmm Meson build: Improve internal dependencies

[Kjell Ahlstedt <kjellahl src gnome org>]

commit d9533d4e5fde228b985ac15764241fb76d231713
Author: Kjell Ahlstedt <kjellahlstedt gmail com>
Date:   Mon Jan 13 18:48:50 2020 +0100

    skeletonmm Meson build: Improve internal dependencies
    
    * skeletonmm/doc/reference/meson.build: Less difference between
    maintainer-mode and not maintainer-mode.
    * keletonmm/skeleton/skeletonmm/meson.build: Make separate lists of
    built .h files and built .cc files.

 skeletonmm/doc/reference/meson.build       | 54 +++++++++++++-----------------
 skeletonmm/skeleton/skeletonmm/meson.build | 24 +++++++------
 2 files changed, 38 insertions(+), 40 deletions(-)
---
diff --git a/skeletonmm/doc/reference/meson.build b/skeletonmm/doc/reference/meson.build
index 7344252..1ff7194 100644
--- a/skeletonmm/doc/reference/meson.build
+++ b/skeletonmm/doc/reference/meson.build
@@ -1,7 +1,7 @@
 # doc/reference
 
 # Input: built_files_root, project_source_root, skeletonmm_pcname, perl,
-#        hg_ccg_basenames, extra_h_files, built_file_targets, install_datadir,
+#        hg_ccg_basenames, extra_h_files, built_h_file_targets, install_datadir,
 #        dist_cmd, python3
 # Output: install_docdir, install_devhelpdir
 
@@ -81,40 +81,34 @@ src_h_files += project_source_root / 'skeleton' / 'skeletonmm.h'
 doctool_dir = project_source_root / 'untracked' / 'doc' # MMDOCTOOLDIR
 doctool_dist_dir = 'untracked' / 'doc' # Relative to MESON_DIST_ROOT
 
-if built_file_targets.length() > 0
+doc_h_files = src_h_files
+if built_h_file_targets.length() > 0
   # .h files have been generated from .hg files (maintainer mode).
-  tag_file = custom_target('html_and_tag',
-    input: src_h_files,
-    output: book_name + '.tag',
-    command: [
-      python3, doc_reference, 'doxygen',
-      doctool_dir,
-      '@OUTPUT@',
-      built_h_files,
-      '@INPUT@',
-    ],
-    build_by_default: build_documentation,
-    depends: built_file_targets,
-    install: true,
-    install_dir: install_reference_docdir,
-  )
+  # Use built_h_file_targets instead of built_h_files here, or else Meson won't
+  # know that Doxygen must not be executed until the .h files have been built.
+  doc_h_files += built_h_file_targets
 else
   # All .h files are stored in the source tree (not maintainer mode).
-  tag_file = custom_target('html_and_tag',
-    input: src_h_files + built_h_files,
-    output: book_name + '.tag',
-    command: [
-      python3, doc_reference, 'doxygen',
-      doctool_dir,
-      '@OUTPUT@',
-      '@INPUT@',
-    ],
-    build_by_default: build_documentation,
-    install: true,
-    install_dir: install_reference_docdir,
-  )
+  doc_h_files += built_h_files
 endif
 
+# Can't use @INPUT@ in the command. It requires absolute file paths.
+# Paths in built_h_file_targets are relative to project_build_root.
+tag_file = custom_target('html_and_tag',
+  input: doc_h_files,
+  output: book_name + '.tag',
+  command: [
+    python3, doc_reference, 'doxygen',
+    doctool_dir,
+    '@OUTPUT@',
+    src_h_files,
+    built_h_files,
+  ],
+  build_by_default: build_documentation,
+  install: true,
+  install_dir: install_reference_docdir,
+)
+
 devhelp_file = custom_target('devhelp',
   input: tag_file,
   output: book_name + '.devhelp2',
diff --git a/skeletonmm/skeleton/skeletonmm/meson.build b/skeletonmm/skeleton/skeletonmm/meson.build
index ae36c58..89e9373 100644
--- a/skeletonmm/skeleton/skeletonmm/meson.build
+++ b/skeletonmm/skeleton/skeletonmm/meson.build
@@ -3,7 +3,7 @@
 # Input: skeletonmm_build_dep, skeletonmm_pcname, maintainer_mode, project_source_root,
 #        generate_binding, m4_files, skeletonmm_libversion, install_includedir,
 #        dist_cmd, python3
-# Output: hg_ccg_basenames, extra_h_files, built_file_targets, built_files_root,
+# Output: hg_ccg_basenames, extra_h_files, built_h_file_targets, built_files_root,
 #         skeletonmm_dep
 
 defs_basefiles = [
@@ -43,6 +43,11 @@ if maintainer_mode
 
   # doc/reference/meson.build needs this.
   built_files_root = project_build_root
+  built_h_file_targets = []
+
+  # Force meson+ninja to generate source files before anything is compiled.
+  # Compilation must depend on these targets.
+  built_cc_file_targets = []
 
   hg_files = []
   foreach file : hg_ccg_basenames
@@ -50,7 +55,7 @@ if maintainer_mode
   endforeach
 
   # Create wrap_init.cc in project_build_root/skeleton/skeletonmm.
-  wrap_init_target = custom_target('wrap_init.cc',
+  built_cc_file_targets += custom_target('wrap_init.cc',
     input: hg_files,
     output: 'wrap_init.cc',
     command: [
@@ -64,17 +69,13 @@ if maintainer_mode
     install: false,
   )
 
-  # Force meson+ninja to generate source files before anything is compiled.
-  # Compilation must depend on these targets.
-  built_file_targets = []
-
   # Create .h/_p.h/.cc files from .hg/.ccg files in project_build_root/skeleton/skeletonmm.
   foreach file : hg_ccg_basenames
     hg_file = '..' / 'src' / file + '.hg'
     ccg_file = '..' / 'src' / file + '.ccg'
-    built_file_targets += custom_target(file + '.cc',
+    built_file_target = custom_target(file + '.cc',
       input: [hg_file, ccg_file],
-      output: [file + '.stamp', file + '.cc'],
+      output: [file + '.stamp', file + '.cc', file + '.h'],
       command: [
         python3, generate_binding, 'gmmproc',
         gmmproc_dir,
@@ -87,11 +88,13 @@ if maintainer_mode
       build_by_default: maintainer_mode,
       install: false,
     )
+    built_cc_file_targets += built_file_target[1]
+    built_h_file_targets += built_file_target[2]
   endforeach
 
   extra_include_dirs = ['..']
   skeletonmm_library = library(skeletonmm_pcname,
-    wrap_init_target, built_file_targets, extra_cc_files,
+    built_cc_file_targets, built_h_file_targets, extra_cc_files,
     version: skeletonmm_libversion,
     include_directories: extra_include_dirs,
     dependencies: skeletonmm_build_dep,
@@ -106,8 +109,8 @@ else # not maintainer_mode
   # project_source_root/untracked/skeleton/skeletonmm.
 
   # doc/reference/meson.build needs these.
-  built_file_targets = []
   built_files_root = project_source_root / 'untracked'
+  built_h_file_targets = []
 
   # Two cases:
   # 1. The source code comes from a tarball, where the built files
@@ -166,6 +169,7 @@ endif
 # This is useful in the main project when skeletonmm is used as a subproject.
 # It's also used when building example programs and test programs.
 skeletonmm_dep = declare_dependency(
+  sources: built_h_file_targets,
   link_with: skeletonmm_library,
   include_directories: extra_include_dirs,
   dependencies: skeletonmm_build_dep