[CMake][Ninja] Allow configuration of link/compile pool sizes

https://bugs.webkit.org/show_bug.cgi?id=249221

Reviewed by NOBODY (OOPS\!).

* Source/cmake/WebKitCommon.cmake: Check environment for new
  variables to set the default link pool size (otherwise
  configure as before), also check for compile pool size
  and if present set up a pool for compile tasks.

Canonical link: https://commits.webkit.org/257800@main

Source/cmake/WebKitCommon.cmake

@@ -235,14 +235,21 @@ if (NOT HAS_RUN_WEBKIT_COMMON)
     endif ()
 
     # -----------------------------------------------------------------------------
-    # Job pool to avoid running too many memory hungry linker processes
+    # Job pool to avoid running too many memory hungry processes
     # -----------------------------------------------------------------------------
-    if (${CMAKE_BUILD_TYPE} STREQUAL "Release" OR ${CMAKE_BUILD_TYPE} STREQUAL "MinSizeRel")
-        set_property(GLOBAL PROPERTY JOB_POOLS link_pool_jobs=4)
+    if (DEFINED ENV{WEBKIT_NINJA_LINK_MAX})
+        list(APPEND WK_POOLS "link_pool_jobs=$ENV{WEBKIT_NINJA_LINK_MAX}")
+    elseif (${CMAKE_BUILD_TYPE} STREQUAL "Release" OR ${CMAKE_BUILD_TYPE} STREQUAL "MinSizeRel")
+        list(APPEND WK_POOLS link_pool_jobs=4)
     else ()
-        set_property(GLOBAL PROPERTY JOB_POOLS link_pool_jobs=2)
+        list(APPEND WK_POOLS link_pool_jobs=2)
     endif ()
     set(CMAKE_JOB_POOL_LINK link_pool_jobs)
+    if (DEFINED ENV{WEBKIT_NINJA_COMPILE_MAX})
+        list(APPEND WK_POOLS "compile_pool_jobs=$ENV{WEBKIT_NINJA_COMPILE_MAX}")
+        set(CMAKE_JOB_POOL_COMPILE compile_pool_jobs)
+    endif ()
+    set_property(GLOBAL PROPERTY JOB_POOLS ${WK_POOLS})
 
     # -----------------------------------------------------------------------------
     # Create derived sources directories