depends: Do not force Precompiled Headers (PCH) for building Qt on Linux

On CentOS 8 the forced '-pch' option breaks Qt build.
Removing '-pch' option does not affect build time for other Linux
systems.

ci/test/00_setup_env_i686_centos.sh

@@ -11,7 +11,6 @@ export CONTAINER_NAME=ci_i686_centos_8
 export DOCKER_NAME_TAG=centos:8
 export DOCKER_PACKAGES="gcc-c++ glibc-devel.x86_64 libstdc++-devel.x86_64 glibc-devel.i686 libstdc++-devel.i686 ccache libtool make git python3 python3-zmq which patch lbzip2 dash rsync coreutils"
 export GOAL="install"
-export DEP_OPTS="NO_QT=1"  # Gui disabled for now to avoid build failures
-export BITCOIN_CONFIG="--enable-zmq --with-gui=no --enable-reduce-exports --with-boost-process"
+export BITCOIN_CONFIG="--enable-zmq --with-gui=qt5 --enable-reduce-exports --with-boost-process"
 export CONFIG_SHELL="/bin/dash"
 export TEST_RUNNER_ENV="LC_ALL=en_US.UTF-8"

depends/packages/qt.mk

@@ -69,7 +69,6 @@ $(package)_config_opts += -nomake examples
 $(package)_config_opts += -nomake tests
 $(package)_config_opts += -opensource
 $(package)_config_opts += -optimized-tools
-$(package)_config_opts += -pch
 $(package)_config_opts += -pkg-config
 $(package)_config_opts += -prefix $(host_prefix)
 $(package)_config_opts += -qt-libpng
@@ -117,6 +116,7 @@ $(package)_config_opts += -no-feature-xml
 
 $(package)_config_opts_darwin = -no-dbus
 $(package)_config_opts_darwin += -no-opengl
+$(package)_config_opts_darwin += -pch
 
 ifneq ($(build_os),darwin)
 $(package)_config_opts_darwin += -xplatform macx-clang-linux
@@ -149,6 +149,7 @@ $(package)_config_opts_mingw32 = -no-opengl
 $(package)_config_opts_mingw32 += -no-dbus
 $(package)_config_opts_mingw32 += -xplatform win32-g++
 $(package)_config_opts_mingw32 += -device-option CROSS_COMPILE="$(host)-"
+$(package)_config_opts_mingw32 += -pch
 
 $(package)_config_opts_android = -xplatform android-clang
 $(package)_config_opts_android += -android-sdk $(ANDROID_SDK)
@@ -164,6 +165,7 @@ $(package)_config_opts_android += -qt-freetype
 $(package)_config_opts_android += -no-fontconfig
 $(package)_config_opts_android += -L $(host_prefix)/lib
 $(package)_config_opts_android += -I $(host_prefix)/include
+$(package)_config_opts_android += -pch
 
 $(package)_config_opts_aarch64_android += -android-arch arm64-v8a
 $(package)_config_opts_armv7a_android += -android-arch armeabi-v7a