update travis build, make with 4 thread

tools/build_all.py

@@ -4,10 +4,8 @@ import sys
 import subprocess
 import time
 
-PARALLEL = "-j 4"
 travis = False
 if "TRAVIS" in os.environ and os.environ["TRAVIS"] == "true":
-    PARALLEL="-j 2"
     travis = True
 
 success_count = 0
@@ -19,7 +17,7 @@ all_boards = ["metro_m0_express", "metro_m4_express", "pca10056", "feather_nrf52
 
 def build_example(example, board):
     subprocess.run("make -C examples/device/{} BOARD={} clean".format(example, board), shell=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
-    return subprocess.run("make {} -C examples/device/{} BOARD={} all".format(PARALLEL, example, board), shell=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+    return subprocess.run("make -j 4 -C examples/device/{} BOARD={} all".format(example, board), shell=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
 
 total_time = time.monotonic()
 
@@ -52,6 +50,6 @@ for example in all_device_example:
 
 
 total_time = time.monotonic() - total_time
-
 print("Total build time took {:.2f}s".format(total_time))
+
 sys.exit(exit_status)