Update to 2.17.11.

• Trim comments after USE_GCC [1]
• Add a check for redundant SHEBANG_LANG values [2]
• Make sure both USES and USE_* are actually seen before checking to see if one is included before the other [3]

PR: 221085 [1]

		220500 [2]

Submitted by: gerald [1]
Reported by: dbaio [3]