Try to use ninja on CI

cmake/ctest/configure_linux.ctest

@@ -1,16 +1,11 @@
-set(CMAKE_GENERATOR "Unix Makefiles")
+set(CMAKE_GENERATOR "Ninja")
 if($ENV{DEBUG})
     set(BUILD_TYPE "Debug")
 else()
     set(BUILD_TYPE "Release")
 endif()
 set(CONFIGURE_EXTRA_OPTIONS ";")
-include(ProcessorCount)
-ProcessorCount(CORES_COUNT)
 set(BUILD_EXTRA_FLAGS "")
-if(NOT CORES_COUNT EQUAL 0)
-    list(APPEND BUILD_EXTRA_FLAGS "-j${CORES_COUNT}")
-endif()
 
 set(BUILD_TOOLS TRUE)
 set(BUILD_VIEWER TRUE)

scripts/docker/arch_latest.docker

@@ -4,6 +4,7 @@ RUN pacman -Syy --noconfirm \
     core/gcc \
     extra/clang \
     make \
+    ninja \
     extra/boost \
     extra/cmake \
     extra/ffmpeg \

scripts/docker/conan_base.docker

@@ -7,6 +7,7 @@ RUN apt-get update \
         gcc-8 \
         g++-8 \
         clang-6.0 \
+        ninja-build \
             # scripts to install conan \
             python3-pip \
             python3-distutils \

scripts/docker/fedora_latest.docker

@@ -13,6 +13,7 @@ RUN dnf update -y \
         boost-devel \
         cmake \
         make \
+        ninja-build \
         bullet-devel \
         ffmpeg-devel \
         glm-devel \

scripts/docker/ubuntu_latest.docker

@@ -19,6 +19,7 @@ RUN apt-get update \
         libqt5opengl5-dev \
         libfreetype6-dev \
         iwyu \
+        ninja-build \
         qt5-default
 
 CMD ["/bin/bash"]