app, meson: Make python check more robust to work with MacPorts etc

Partially reverts 9be1af2b

See the context: https://gitlab.gnome.org/Infrastructure/gimp-macos-build/-/merge_requests/408#note_2642419

build/macos/1_build-deps-macports.sh

@@ -48,7 +48,6 @@ if [ -f "$OPT_PREFIX/bin/port" ]; then
   if echo "$CI_JOB_NAME" | grep -q 'deps' && { [ "$CI_COMMIT_BRANCH" = "$CI_DEFAULT_BRANCH" ] || [ "$first_cache" ] }; then
     mkdir -p macports-cached-$(uname -m) && cp -fa $OPT_PREFIX/var/macports/* macports-cached-$(uname -m) || true
   fi
-  git apply -v build/macos/patches/0001-meson-Patch-python-version.patch || true
 else
   brew upgrade --quiet
   brew install --quiet $(tr '\\' '\n' < build/macos/all-deps-uni.txt | grep -v '#' | sed -n 's/.*|homebrew://p' | awk '{print $1}' | xargs)

build/macos/patches/0001-meson-Patch-python-version.patch

@@ -1,24 +0,0 @@
-From 9ee6b4e10c0b429358640aac4e081e2aca329ddb Mon Sep 17 00:00:00 2001
-From: Bruno Lopes <brunvonlope@outlook.com>
-Date: Sat, 10 Jan 2026 15:49:22 -0300
-Subject: [PATCH] meson: Patch python version
-
----
- meson.build | 2 +-
- 1 file changed, 1 insertion(+), 1 deletion(-)
-
-diff --git a/meson.build b/meson.build
-index cd51137d6f..b59fb6cceb 100644
---- a/meson.build
-+++ b/meson.build
-@@ -130,7 +130,7 @@ versionconfig.set('GIMP_API_VERSION',   gimp_api_version)
- pkgconfig = import('pkgconfig')
- i18n      = import('i18n')
- gnome     = import('gnome')
--python    = import('python').find_installation()
-+python    = import('python').find_installation('python3.13')
- simd      = import('unstable-simd')
- fs        = import('fs')
-
---
-2.50.1 (Apple Git-155)

meson.build

@@ -130,7 +130,7 @@ versionconfig.set('GIMP_API_VERSION',   gimp_api_version)
 pkgconfig = import('pkgconfig')
 i18n      = import('i18n')
 gnome     = import('gnome')
-python    = import('python').find_installation()
+pythonmod = import('python')
 simd      = import('unstable-simd')
 fs        = import('fs')
 
@@ -1192,23 +1192,54 @@ perl = find_program('perl5', 'perl', 'perl5.005', 'perl5.004', 'perl')
 
 python3_minver = '>=3.6'
 
+pygobject_minver = '>=3.0'
+
+#Non-versioned python
+py_candidates = ['python3']
+#Versioned python (e.g. on MacPorts)
+foreach i : range(python3_minver.substring(2).split('.')[-1].to_int(), 40)
+  py_candidates += ['python3.' + i.to_string()]
+endforeach
+
+python = disabler()
+pygobject_found = ''
+pygobject_gexiv2_found = false
+foreach py : py_candidates
+  #Check if PyGobject installation have pycairo (#13105)
+  python_tmp = pythonmod.find_installation(py, modules: ['gi', 'cairo'], required: false)
+  if python_tmp.found() and python_tmp.language_version().version_compare(python3_minver)
+    python = python_tmp
+    #Check if PyGObject installation have minimum version
+    pygobject_found = run_command(python_tmp, '-c',
+                                  '\n'.join([
+                                  '''import gi''',
+                                  '''print(".".join(map(str, gi.version_info)))''']),
+                                  check: false)
+    #Check if PyGObject installation have gexiv2 (#15179)
+    #(This is specially important on MacPorts where gexiv2 have many python variants)
+    pygobject_gexiv2_found = run_command(python_tmp, '-c',
+                                        '\n'.join([
+                                        '''import sys, gi''',
+                                        '''try:''',
+                                        '''    import gi.repository.GExiv2''',
+                                        '''except (ImportError):''',
+                                        '''    sys.exit(1)''']),
+                                        check: false).returncode() == 0
+    if pygobject_found.returncode() == 0 and pygobject_found.stdout().strip().version_compare(pygobject_minver) and pygobject_gexiv2_found
+      break
+    endif
+  endif
+endforeach
+
+if not python.found() or not python.language_version().version_compare(python3_minver)
+  error('No suitable Python installation found. Minimum supported version: @0@'.format(python3_minver))
+endif
 message('Found Python @0@'.format(python.language_version()))
 
-if not python.language_version().version_compare(python3_minver)
-  error('Minimum supported Python version: @0@'.format(python3_minver))
-endif
-
-pygobject_found = run_command(python, '-c',
-                              '\n'.join([
-                              '''import sys, gi''',
-                              '''version = '@0@' '''.format('3.0'),
-                              '''sys.exit(gi.check_version(version))''']),
-                              check: false).returncode() == 0
-message('Found PyGObject: @0@'.format(pygobject_found))
-
-if not pygobject_found
-  error('PyGObject is required.')
+if pygobject_found.returncode() != 0 or not pygobject_found.stdout().strip().version_compare(pygobject_minver) or not pygobject_gexiv2_found
+  error('No suitable PyGObject (with Pycairo and Gexiv2 modules) found. Minimum supported version: @0@'.format(pygobject_minver))
 endif
+message('Found PyGObject: @0@'.format(pygobject_found.stdout().strip()))
 
 ## Javascript
 
@@ -1271,7 +1302,7 @@ if have_lua
       endif
 
       if is_supported_lua
-        have_lua_lgi = run_command(lua, '-e',
+        have_lua_lgi = run_command(luat, '-e',
                                    '''
                                    local lgi = require 'lgi'
                                    ''',