Comment 2 for bug 1970783

Upstream bugs for CMake and ICU requirements:
* CMake (3.12 then 3.21, Bionic has 3.10): https://bugs.webkit.org/show_bug.cgi?id=221727
* ICU (61.2, Bionic has 60.3): https://bugs.webkit.org/show_bug.cgi?id=229608

When I tried to build the new version (merged from Debian testing and with the requirements on CMake and ICU versions lowered to the versions in Ubuntu 18.04), I got the following error:

-- Platform-specific CMakeLists not found: /home/user/webkit2gtk-2.36.3/Source/bmalloc/PlatformGTK.cmake
CMake Error at Source/cmake/WebKitMacros.cmake:155 (target_link_libraries):
  Object library target "bmalloc" may not link to anything.
Call Stack (most recent call first):
  Source/cmake/WebKitMacros.cmake:299 (_WEBKIT_TARGET)
  Source/bmalloc/CMakeLists.txt:682 (WEBKIT_FRAMEWORK)

-- Configuring incomplete, errors occurred!

All builds of this source package in my PPA do not install the required version of GCC (bug #1979136).