data: Fix obscure environ files on Windows

Following 36b660e2b2

- PATH was being set due to the Installer and MSIX but
  on my tests on both relocatable and Unix-style builds it
  was bogus. C and Py plug-ins worked without problems
- Same aplies to GI_TYPELIB_PATH, it is obscure and useless

data/environ/default.env

@@ -1,4 +1,2 @@
 # Example entry in files like these
 # FOOPATH=/path/to/foo/stuff
-
-@BIN_PATH@

data/environ/meson.build

@@ -1,33 +1,30 @@
 #.env files read by gimp_environ_table_load_env_file in gimpenvirontable.c
 
 
-environ_config = configuration_data()
-if platform_windows and relocatable_bundle
-  environ_config.set('BIN_PATH', 'PATH=${gimp_installation_dir}\\bin')
-else
-  environ_config.set('BIN_PATH', '')
-endif
-
-configure_file(
-  input : 'default.env.in',
-  output: 'default.env',
-  configuration: environ_config,
-  install: true,
+install_data(
+  'default.env',
   install_dir: gimpplugindir / 'environ',
 )
 
 
-if not meson.is_cross_build() and python.found()
-  install_data(
-    'python.env',
-    install_dir: gimpplugindir / 'environ',
-  )
-endif
-
-
-if platform_windows and not meson.is_cross_build() and python.found()
-  install_data(
-    'pygimp.env',
+if relocatable_bundle or platform_windows and not meson.is_cross_build()
+  pygimp_config = configuration_data()
+  if relocatable_bundle
+    pygimp_config.set('DONTWRITEBYTECODE_SETTING', 'PYTHONDONTWRITEBYTECODE=1')
+  else
+    pygimp_config.set('DONTWRITEBYTECODE_SETTING', '')
+  endif
+  if platform_windows 
+    pygimp_config.set('HIGHDPI_SETTING', '__COMPAT_LAYER=HIGHDPIAWARE')
+  else
+    pygimp_config.set('HIGHDPI_SETTING', '')
+  endif
+
+  configure_file(
+    input : 'pygimp.env.in',
+    output: 'pygimp.env',
+    configuration: pygimp_config,
+    install: true,
     install_dir: gimpplugindir / 'environ',
   )
 endif

data/environ/pygimp.env

@@ -1,2 +0,0 @@
-__COMPAT_LAYER=HIGHDPIAWARE
-PYTHONDONTWRITEBYTECODE=1

data/environ/pygimp.env.in

@@ -0,0 +1,2 @@
+@DONTWRITEBYTECODE_SETTING@
+@HIGHDPI_SETTING@

data/environ/python.env

@@ -1 +0,0 @@
-: GI_TYPELIB_PATH=${gimp_installation_dir}/lib/girepository-1.0/