Make Scalar::SChar return an explicit signed type

This is needed for platforms where the default "char" type is unsigned.

Originally committed as part of (now reverted) r266311.

llvm-svn: 266420

lldb/include/lldb/Core/Scalar.h

@@ -254,7 +254,7 @@ public:
     unsigned char
     UChar(unsigned char fail_value = 0) const;
 
-    char
+    signed char
     SChar(char fail_value = 0) const;
 
     unsigned short

lldb/source/Core/Scalar.cpp

@@ -1380,7 +1380,7 @@ Scalar::MakeSigned ()
     return success;
 }
 
-char
+signed char
 Scalar::SChar(char fail_value) const
 {
     switch (m_type)