Convert: Inline platform-specific methods

They don't provide real value.

Source/cmOutputConverter.cxx

@@ -240,9 +240,8 @@ std::string cmOutputConverter::EscapeForShell(const std::string& str,
     flags |= Shell_Flag_NMake;
   }
 
-  return this->GetState()->UseWindowsShell()
-    ? Shell_GetArgumentForWindows(str.c_str(), flags)
-    : Shell_GetArgumentForUnix(str.c_str(), flags);
+  return Shell__GetArgument(str.c_str(), !this->GetState()->UseWindowsShell(),
+                           flags);
 }
 
 std::string cmOutputConverter::EscapeForCMake(const std::string& str)
@@ -271,7 +270,7 @@ std::string cmOutputConverter::EscapeForCMake(const std::string& str)
 std::string cmOutputConverter::EscapeWindowsShellArgument(const char* arg,
                                                           int shell_flags)
 {
-  return Shell_GetArgumentForWindows(arg, shell_flags);
+  return Shell__GetArgument(arg, 0, shell_flags);
 }
 
 cmOutputConverter::FortranFormat cmOutputConverter::GetFortranFormat(
@@ -632,15 +631,3 @@ std::string cmOutputConverter::Shell__GetArgument(const char* in, int isUnix,
 
   return out.str();
 }
-
-std::string cmOutputConverter::Shell_GetArgumentForWindows(const char* in,
-                                                           int flags)
-{
-  return Shell__GetArgument(in, 0, flags);
-}
-
-std::string cmOutputConverter::Shell_GetArgumentForUnix(const char* in,
-                                                        int flags)
-{
-  return Shell__GetArgument(in, 1, flags);
-}

Source/cmOutputConverter.h

@@ -33,8 +33,7 @@ public:
   void SetLinkScriptShell(bool linkScriptShell);
 
   /**
-   * Flags to pass to Shell_GetArgumentForWindows or
-   * Shell_GetArgumentForUnix.  These modify the generated
+   * Flags to pass to Shell_GetArgument.  These modify the generated
    * quoting and escape sequences to work under alternative
    * environments.
    */
@@ -70,16 +69,6 @@ public:
     Shell_Flag_WatcomQuote = (1 << 7)
   };
 
-  /**
-   * Transform the given command line argument for use in a Windows or
-   * Unix shell.  Returns a pointer to the end of the command line
-   * argument in the provided output buffer.  Flags may be passed to
-   * modify the generated quoting and escape sequences to work under
-   * alternative environments.
-   */
-  static std::string Shell_GetArgumentForWindows(const char* in, int flags);
-  static std::string Shell_GetArgumentForUnix(const char* in, int flags);
-
   std::string EscapeForShell(const std::string& str, bool makeVars = false,
                              bool forEcho = false,
                              bool useWatcomQuote = false) const;