1 files changed, 19 insertions, 0 deletions
diff --git a/pkgs/stdenv/generic/setup.sh b/pkgs/stdenv/generic/setup.sh
index 5e2fc7b24dbe6..948b6ca3ad667 100644
--- a/pkgs/stdenv/generic/setup.sh
+++ b/pkgs/stdenv/generic/setup.sh
@@ -269,6 +269,23 @@ fi
 export NIX_INDENT_MAKE=1
 
 
+# Normalize the NIX_BUILD_CORES variable. The value might be 0, which
+# means that we're supposed to try and auto-detect the number of
+# available CPU cores at run-time.
+
+if test -z "${NIX_BUILD_CORES:-}"; then
+  NIX_BUILD_CORES="1"
+elif test "$NIX_BUILD_CORES" -le 0; then
+  NIX_BUILD_CORES=$(nproc 2>/dev/null || true)
+  if expr >/dev/null 2>&1 "$NIX_BUILD_CORES" : "^[0-9][0-9]*$"; then
+    :
+  else
+    NIX_BUILD_CORES="1"
+  fi
+fi
+export NIX_BUILD_CORES
+
+
 ######################################################################
 # Misc. helper functions.
 
@@ -603,6 +620,7 @@ buildPhase() {
 
     echo "make flags: $makeFlags ${makeFlagsArray[@]} $buildFlags ${buildFlagsArray[@]}"
     make ${makefile:+-f $makefile} \
+        ${enableParallelBuilding:+-j${NIX_BUILD_CORES} -l${NIX_BUILD_CORES}} \
         $makeFlags "${makeFlagsArray[@]}" \
         $buildFlags "${buildFlagsArray[@]}"
 
@@ -615,6 +633,7 @@ checkPhase() {
 
     echo "check flags: $makeFlags ${makeFlagsArray[@]} $checkFlags ${checkFlagsArray[@]}"
     make ${makefile:+-f $makefile} \
+        ${enableParallelBuilding:+-j${NIX_BUILD_CORES} -l${NIX_BUILD_CORES}} \
         $makeFlags "${makeFlagsArray[@]}" \
         $checkFlags "${checkFlagsArray[@]}" ${checkTarget:-check}