debuggers/gdb: use a more standard install location.

Same as 4922edf269,
just mirrored here.

doc/changelog.dox

@@ -79,8 +79,9 @@ See also:
 -   Added MSVC Natvis files and pretty-printers for GDB. See @ref debuggers,
     [mosra/magnum#589](https://github.com/mosra/magnum/pull/589),
     [mosra/magnum#595](https://github.com/mosra/magnum/pull/595),
-    [mosra/magnum#620](https://github.com/mosra/magnum/pull/620) and
-    [mosra/magnum#623](https://github.com/mosra/magnum/pull/623) for more
+    [mosra/magnum#620](https://github.com/mosra/magnum/pull/620),
+    [mosra/magnum#623](https://github.com/mosra/magnum/pull/623) and
+    [mosra/corrade#179](https://github.com/mosra/corrade/issues/179) for more
     information.
 
 @subsubsection changelog-latest-new-debugtools DebugTools library

doc/debuggers.dox

@@ -36,20 +36,19 @@ The [src/debuggers/gdb](https://github.com/mosra/magnum/tree/master/src/debugger
 directory contains [GDB pretty printers](https://sourceware.org/gdb/onlinedocs/gdb/Pretty-Printing.html)
 for important types in the @ref Magnum and @ref Animation namespace and most
 @ref Math classes. Contents of this directory are also copied into
-@cb{.sh} ${CMAKE_PREFIX_PATH}/share/magnum/debuggers/gdb @ce during
-installation, where the prefix is usually `/usr` or `/usr/local`.
+@cb{.sh} ${CMAKE_INSTALL_PREFIX}/share/gdb/python @ce during installation,
+where the prefix is usually `/usr` or `/usr/local`.
 
 Easiest is to auto-load them on startup, by putting the following snippet into
 the user-specific `~/.gdbinit` or `~/.config/gdb/gdbinit` file:
 
 @code{.py}
 python
-import sys
-# Adapt this path to the actual install location (or Magnum's src/ directory).
-# Not pointing to the debuggers subdirectory here because it could conflict
-# with the built-in GDB module.
-sys.path.insert(0, '/usr/share')
-from magnum.debuggers.gdb import register_magnum_printers
+# If not installing into /usr, you'll need to insert the install location (or
+# the src/debuggers/gdb/ directory inside Magnum sources) to Python's path:
+#import sys
+#sys.path.insert(0, '/magnum/install/prefix/share/gdb/python')
+from magnum import register_magnum_printers
 register_magnum_printers(gdb.current_objfile())
 end
 @endcode
@@ -71,8 +70,9 @@ See also @ref corrade-debuggers-gdb-pretty-printers "Corrade GDB pretty printers
 
 The [src/debuggers/natvis](https://github.com/mosra/magnum/tree/master/src/debuggers/natvis)
 directory contains MSVC natvis files for important @ref Math classes. Contents
-of this directory are also copied into @cb{.sh} ${CMAKE_PREFIX_PATH}/share/magnum/debuggers/natvis @ce
-during installation.
+of this directory are also copied into
+@cb{.sh} ${CMAKE_INSTALL_PREFIX}/share/magnum/debuggers/natvis @ce during
+installation.
 
 Easiest way to use is to copy them to the user-specific Natvis directory for
 given version of Visual Studio, such as @cb{.bat} %USERPROFILE%/Documents/Visual Studio 2022/Visualizers @ce.

src/debuggers/CMakeLists.txt

@@ -26,7 +26,7 @@
 
 # TODO: same TODOs as in corrade/src/debuggers/CMakeLists.txt apply here
 if(NOT CORRADE_TARGET_MSVC AND NOT CORRADE_TARGET_EMSCRIPTEN)
-    install(DIRECTORY gdb DESTINATION ${MAGNUM_DATA_INSTALL_DIR}/debuggers)
+    install(DIRECTORY gdb/magnum DESTINATION share/gdb/python)
 endif()
 
 if(CORRADE_TARGET_MSVC)