diff --git a/build-cmakelibs.sh b/build-cmakelibs.sh
index c8131bac..8f41437e 100755
--- a/build-cmakelibs.sh
+++ b/build-cmakelibs.sh
@@ -125,7 +125,7 @@ popd
 ##
 ## Build cmake projects
 ##
-build zlib -DUNIX:BOOL=ON -DZLIB_BUILD_EXAMPLES=OFF
+PROC_NR=1 build zlib -DUNIX:BOOL=ON -DZLIB_BUILD_EXAMPLES=OFF
 build xz -DTUKLIB_CPUCORES_FOUND=ON -DTUKLIB_PHYSMEM_FOUND=ON -DHAVE_GETOPT_LONG=OFF -DBUILD_TESTING=OFF
 build lz4/build/cmake -DLZ4_POSITION_INDEPENDENT_LIB=OFF -DLZ4_BUILD_CLI=OFF -DLZ4_BUILD_LEGACY_LZ4C=OFF
 build libzip -DBUILD_TOOLS=OFF -DBUILD_REGRESS=OFF