Compile once

compile_once - Control whether runtime classes are recompiled when no change is detected

Synopsis
host% gridlabd -D compile_once=TRUE|FALSE
 * 1) set compile_once=TRUE|FALSE

Description
When GridLAB-D loads a GLM file and encounters C/C++ source code, it invokes a compiler. If the GLM file is newer than the object code, the compiler is normally not invoked (compile_once=TRUE. When compile_once==FALSE, the compiler is invoke every time the GLM file is loaded.  This can be important if compile flags or dependencies exist that the GLM loader does not recognize.