Adds accessor methods to class ClFlags.

Allows one to define explicit overrides in get accessors, based on
compilation features. To show usage, modified SubConstantCalls to
never be enabled if building a minimal llvm2ice.

BUG=None
R=stichnot@chromium.org

Review URL: https://codereview.chromium.org/905463003

Makefile.standalone

diff --git a/Makefile.standalone b/Makefile.standalone
index 36026de..8f42561 100644
--- a/Makefile.standalone
+++ b/Makefile.standalone
@@ -54,10 +54,12 @@
   NOASSERT = 1
   OBJDIR := $(OBJDIR)+Min
   CXX_DEFINES += -DALLOW_DUMP=0 -DALLOW_LLVM_CL=0 -DALLOW_LLVM_IR=0 \
-	-DALLOW_LLVM_IR_AS_INPUT=0 -DALLOW_DISABLE_IR_GEN=0
+	-DALLOW_LLVM_IR_AS_INPUT=0 -DALLOW_DISABLE_IR_GEN=0 \
+        -DALLOW_MINIMAL_BUILD=1
 else
   CXX_DEFINES += -DALLOW_DUMP=1 -DALLOW_LLVM_CL=1 -DALLOW_LLVM_IR=1 \
-	-DALLOW_LLVM_IR_AS_INPUT=1 -DALLOW_DISABLE_IR_GEN=1
+	-DALLOW_LLVM_IR_AS_INPUT=1 -DALLOW_DISABLE_IR_GEN=1 \
+        -DALLOW_MINIMAL_BUILD=0
 endif
 
 ifdef NOASSERT