Fixing Node.js v0.8.2 Build on Linux

There's a nasty gcc bug on RedHat (RHEL 6) and CentOS Linux (and related) that gets triggered when you try to build Node.js v0.8.2: pure virtual method called.

Solution: Run make install CFLAGS+=-O2 CXXFLAGS+=-O2 instead of just make install.

More info:

• Cannot compile node.js 0.8.2 under CentOS 6.2
• "make install": terminate called without an active exception
• build: fix spurious mksnapshot crashes for good