build: try to autodetect the number of CPU threads available and tweak the

parallel builds accordingly.

build/lol-build

@@ -31,12 +31,39 @@ set -e
 action="$1"
 platform="$2"
 
+###############################################################################
+# Initialisation code
+#
+#  - sets the top_srcdir variable
+#  - sets the LOL_PARALLEL variable
+#  - fix PATH and MKPATH if necessary
+#
 __init__()
 {
     top_srcdir="$(dirname "$0")/.."
     cd "$top_srcdir"
     top_srcdir="`pwd`"
 
+    case "$cpu_count" in
+      [1-9]|[1-9][0-9]|[1-9][0-9][0-9]) ;;
+      *) if [ -r "/proc/cpuinfo" ]; then
+           cpu_count="$(grep -c '^processor\>' /proc/cpuinfo)"
+         fi ;;
+    esac
+    case "$cpu_count" in
+      [1-9]|[1-9][0-9]|[1-9][0-9][0-9]) ;;
+      *) cpu_count="$(sysctl -n hw.ncpu 2>/dev/null)" ;;
+    esac
+    case "$cpu_count" in
+      [1-9]|[1-9][0-9]|[1-9][0-9][0-9]) ;;
+      *) cpu_count=1 ;;
+    esac
+    case "$cpu_count" in
+      1) LOL_PARALLEL=1 ;;
+      2) LOL_PARALLEL=3 ;;
+      *) LOL_PARALLEL="$(expr $cpu_count '*' 3 / 2)" ;;
+    esac
+
     case "${MSYSTEM}" in
         MINGW32|MINGW64)
             PATH="$PATH:./contrib/gtk-2.22.1/bin"
@@ -188,7 +215,7 @@ build()
             ant compile
             ;;
         *)
-            make -j6
+            make -j$LOL_PARALLEL
             ;;
     esac
 }