only accept JOBS via make setting and default to 1 - closes #2430

INSTALL.md

@@ -9,6 +9,13 @@ To configure and build Mapnik do:
     $ make
 ```
 
+To trigger parallel compilation you can pass a JOBS value to make:
+
+```bash
+    $ JOBS=4 make
+```
+
+
 To use a Python interpreter that is not named `python` for your build, do
 something like the following instead:
 

Makefile

@@ -5,12 +5,6 @@ PYTHON = python
 
 ifeq ($(JOBS),)
 	JOBS:=1
-	ifeq ($(OS),Linux)
-		JOBS:=$(shell grep -c ^processor /proc/cpuinfo)
-	endif
-	ifeq ($(OS),Darwin)
-		JOBS:=$(shell sysctl -n hw.ncpu)
-	endif
 endif
 
 all: mapnik

SConstruct

@@ -396,7 +396,6 @@ opts.AddVariables(
     ListVariable('BINDINGS','Language bindings to build','all',['python']),
     EnumVariable('THREADING','Set threading support','multi', ['multi','single']),
     EnumVariable('XMLPARSER','Set xml parser','libxml2', ['libxml2','ptree']),
-    ('JOBS', 'Set the number of parallel compilations', "1", lambda key, value, env: int(value), int),
     BoolVariable('DEMO', 'Compile demo c++ application', 'True'),
     BoolVariable('PGSQL2SQLITE', 'Compile and install a utility to convert postgres tables to sqlite', 'False'),
     BoolVariable('SHAPEINDEX', 'Compile and install a utility to generate shapefile indexes in the custom format (.index) Mapnik supports', 'True'),
@@ -1910,9 +1909,6 @@ if not HELP_REQUESTED:
         SetOption('implicit_cache', 1)
         SetOption('max_drift', 1)
 
-    if env['JOBS'] > 1:
-        SetOption("num_jobs", env['JOBS'])
-
     # Build agg first, doesn't need anything special
     if env['RUNTIME_LINK'] == 'shared':
         SConscript('deps/agg/build.py')