Adds a shell script to help build the H3 toolchains (#7299)
Adds a shell script to help build the H3 toolchains (#7299)


pbchou/trafficserver,duke8253/trafficserver,pbchou/trafficserver,vmamidi/trafficserver,duke8253/trafficserver,vmamidi/trafficserver,duke8253/trafficserver,vmamidi/trafficserver,duke8253/trafficserver,duke8253/trafficserver,pbchou/trafficserver,pbchou/trafficserver,SolidWallOfCode/trafficserver,bryancall/trafficserver,bryancall/trafficserver,bryancall/trafficserver,SolidWallOfCode/trafficserver,SolidWallOfCode/trafficserver,pbchou/trafficserver,duke8253/trafficserver,vmamidi/trafficserver,duke8253/trafficserver,bryancall/trafficserver,SolidWallOfCode/trafficserver,pbchou/trafficserver,bryancall/trafficserver,SolidWallOfCode/trafficserver,SolidWallOfCode/trafficserver,vmamidi/trafficserver,SolidWallOfCode/trafficserver,bryancall/trafficserver,vmamidi/trafficserver