Use CMake's -B, --build, and --install options

util/ci/build.sh

@@ -1,8 +1,6 @@
 #! /bin/bash -e
 
-mkdir build
-cd build
-cmake -DCMAKE_BUILD_TYPE=Debug \
+cmake -B build -DCMAKE_BUILD_TYPE=Debug \
 	-DRUN_IN_PLACE=TRUE -DENABLE_GETTEXT=TRUE \
-	-DBUILD_SERVER=TRUE ${CMAKE_FLAGS} ..
-make -j$(($(nproc) + 1))
+	-DBUILD_SERVER=TRUE ${CMAKE_FLAGS}
+cmake --build build --parallel $(($(nproc) + 1))

util/ci/clang-tidy.sh

@@ -1,15 +1,11 @@
 #! /bin/bash -eu
 
-mkdir -p build
-cd build
-cmake -DCMAKE_BUILD_TYPE=Debug \
+cmake -B build -DCMAKE_BUILD_TYPE=Debug \
 	-DCMAKE_EXPORT_COMPILE_COMMANDS=ON \
 	-DRUN_IN_PLACE=TRUE \
 	-DENABLE_{GETTEXT,SOUND}=FALSE \
-	-DBUILD_SERVER=TRUE ..
-make GenerateVersion
-
-cd ..
+	-DBUILD_SERVER=TRUE
+cmake --build build --target GenerateVersion
 
 ./util/ci/run-clang-tidy.py \
 	-clang-tidy-binary=clang-tidy-9 -p build \