Update build for gcc 4.8.x:

* Use gcc 4.8.x, boost 1.54
* Honor CC,CXX,PATH environment variables
* Prevent compilation with unsupported toolchains
* Print g++ version during Travis build
* Run built-in unit tests after Travis build

.travis.yml

@@ -3,8 +3,18 @@ compiler:
   - gcc
 before_install:
   - sudo apt-get update -qq
-  - sudo apt-get install -qq libboost1.48-all-dev protobuf-compiler libprotobuf-dev libssl-dev exuberant-ctags
-script: scons && npm install && npm test
+  - sudo apt-get install -qq python-software-properties
+  - sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test
+  - sudo add-apt-repository -y ppa:boost-latest/ppa
+  - sudo apt-get update -qq
+  - sudo apt-get install -qq libboost1.54-all-dev protobuf-compiler libprotobuf-dev libssl-dev exuberant-ctags
+  - sudo apt-get install -qq gcc-4.8
+  - sudo apt-get install -qq g++-4.8
+  - sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.8 40 --slave /usr/bin/g++ g++ /usr/bin/g++-4.8
+  - sudo update-alternatives --set gcc /usr/bin/gcc-4.8
+  - g++ -v
+
+script: scons && ./build/rippled --unittest && npm install && npm test
 notifications:
   email:
     false

SConstruct

@@ -8,6 +8,7 @@ import glob
 import os
 import platform
 import re
+import sys
 
 OSX = bool(platform.mac_ver()[0])
 FreeBSD = bool('FreeBSD' == platform.system())
@@ -16,6 +17,8 @@ Ubuntu  = bool(Linux and 'Ubuntu' == platform.linux_distribution()[0])
 Debian  = bool(Linux and 'debian' == platform.linux_distribution()[0])
 Archlinux  = bool(Linux and ('','','') == platform.linux_distribution()) #Arch still has issues with the platform module
 
+USING_CLANG = OSX
+
 #
 # We expect this to be set
 # 
@@ -33,8 +36,12 @@ else:
 # scons tools
 #
 
+HONOR_ENVS = ['CC', 'CXX', 'PATH']
+
 env = Environment(
-    tools = ['default', 'protoc']
+    tools = ['default', 'protoc'],
+    #ENV = dict((k, os.environ[k]) for k in HONOR_ENVS)
+    ENV = dict((k, os.environ[k]) for k in HONOR_ENVS if k in os.environ)
 )
 
 # Use a newer gcc on FreeBSD
@@ -251,9 +258,18 @@ env.Append(CXXFLAGS = ['-O1', '-pthread', '-Wno-invalid-offsetof', '-Wformat']+D
 #
 env.Append(CXXFLAGS = ['-frtti'])
 
-if (int(GCC_VERSION[0]) == 4 and int(GCC_VERSION[1]) == 6):
-    env.Append(CXXFLAGS = ['-std=c++0x'])
-elif (int(GCC_VERSION[0]) > 4 or (int(GCC_VERSION[0]) == 4 and int(GCC_VERSION[1]) >= 7)):
+UBUNTU_GCC_48_INSTALL_STEPS = '''
+https://ripple.com/wiki/Ubuntu_build_instructions#Ubuntu_versions_older_than_13.10_:_Install_gcc_4.8'''
+
+if not USING_CLANG:
+    if (int(GCC_VERSION[0]) == 4 and int(GCC_VERSION[1]) < 8):
+        print "\nrippled, using c++11, requires g++ version >= 4.8 to compile"
+
+        if Ubuntu:
+          print UBUNTU_GCC_48_INSTALL_STEPS
+
+        sys.exit(1)
+    else:
         env.Append(CXXFLAGS = ['-std=c++11'])
 
 # FreeBSD doesn't support O_DSYNC