meson.build: only set build variables for non-default values

Some preprocessor -Defines have defaults set in the source code when
they have not been provided to the C compiler. In this case, there is
no need to pass them on the command-line, unless the build requires a
non-standard value.

The build variables for DEFAULT_EDITOR and DEFAULT_PAGER have appropriate
defaults ('vi' and 'less') set in the code. Add the preprocessor -Defines
to the 'libgit_c_args' only if the values set with the corresponding
'options' are different to these standard values.

Also, the 'git-var' documentation contains some conditional text which
documents the chosen compiled in value, which would not read well for
the standard values. Similar to the above, only add the corresponding
'-a' attribute arguments to the 'asciidoc_common_options' variable, if
the values set in the 'options' are different to these standard values.

Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: ramsay-jones

Documentation/meson.build

@@ -242,6 +242,16 @@ if docs_backend == 'asciidoc'
     '--attribute=build_dir=' + meson.current_build_dir(),
   ]
 
+  pager_opt = get_option('default_pager')
+  if pager_opt != '' and pager_opt != 'less'
+    asciidoc_common_options += '-agit-default-pager=' + pager_opt
+  endif
+
+  editor_opt = get_option('default_editor')
+  if editor_opt != '' and editor_opt != 'vi'
+    asciidoc_common_options += '-agit-default-editor=' + editor_opt
+  endif
+
   documentation_deps = [
     asciidoc_conf,
   ]
@@ -279,6 +289,16 @@ elif docs_backend == 'asciidoctor'
     '--require', 'asciidoctor-extensions',
   ]
 
+  pager_opt = get_option('default_pager')
+  if pager_opt != '' and pager_opt != 'less'
+    asciidoc_common_options += '-agit-default-pager=' + pager_opt
+  endif
+
+  editor_opt = get_option('default_editor')
+  if editor_opt != '' and editor_opt != 'vi'
+    asciidoc_common_options += '-agit-default-editor=' + editor_opt
+  endif
+
   documentation_deps = [
     asciidoctor_extensions,
   ]

meson.build

@@ -693,10 +693,8 @@ endif
 # These variables are used for building libgit.a.
 libgit_c_args = [
   '-DBINDIR="' + get_option('bindir') + '"',
-  '-DDEFAULT_EDITOR="' + get_option('default_editor') + '"',
   '-DDEFAULT_GIT_TEMPLATE_DIR="' + get_option('datadir') / 'git-core/templates' + '"',
   '-DDEFAULT_HELP_FORMAT="' + get_option('default_help_format') + '"',
-  '-DDEFAULT_PAGER="' + get_option('default_pager') + '"',
   '-DETC_GITATTRIBUTES="' + get_option('gitattributes') + '"',
   '-DETC_GITCONFIG="' + get_option('gitconfig') + '"',
   '-DFALLBACK_RUNTIME_PREFIX="' + get_option('prefix') + '"',
@@ -708,6 +706,17 @@ libgit_c_args = [
   '-DPAGER_ENV="' + get_option('pager_environment') + '"',
   '-DSHELL_PATH="' + fs.as_posix(shell.full_path()) + '"',
 ]
+
+editor_opt = get_option('default_editor')
+if editor_opt != '' and editor_opt != 'vi'
+  libgit_c_args += '-DDEFAULT_EDITOR="' + editor_opt + '"'
+endif
+
+pager_opt = get_option('default_pager')
+if pager_opt != '' and pager_opt != 'less'
+  libgit_c_args += '-DDEFAULT_PAGER="' + pager_opt + '"'
+endif
+
 libgit_include_directories = [ '.' ]
 libgit_dependencies = [ ]