EShTargetSpv: Fix #1235, spelling, in a backward compatible way.

StandAlone/StandAlone.cpp

@@ -855,7 +855,7 @@ void CompileAndLinkShaderUnits(std::vector<ShaderCompUnit> compUnits)
                                                                 : glslang::EShSourceGlsl,
                                         compUnit.stage, glslang::EShClientVulkan, ClientInputSemanticsVersion);
                 shader->setEnvClient(glslang::EShClientVulkan, VulkanClientVersion);
-                shader->setEnvTarget(glslang::EshTargetSpv, TargetVersion);
+                shader->setEnvTarget(glslang::EShTargetSpv, TargetVersion);
             } else {
                 shader->setEnvInput((Options & EOptionReadHlsl) ? glslang::EShSourceHlsl
                                                                 : glslang::EShSourceGlsl,

glslang/Public/ShaderLang.h

@@ -119,7 +119,8 @@ typedef enum {
 
 typedef enum {
     EShTargetNone,
-    EshTargetSpv,
+    EShTargetSpv,                 // preferred spelling
+    EshTargetSpv = EShTargetSpv,  // legacy spelling
 } EShTargetLanguage;
 
 struct TInputLanguage {