try to get around linux compiler grief

string/obsolete/nsString2.h

@@ -442,7 +442,10 @@ public:
   nsString& operator+=(const nsStr& aString){return Append(aString,aString.mLength);}
   nsString& operator+=(const nsString& aString){return Append(aString,aString.mLength);}
   nsString& operator+=(const char* aCString) {return Append(aCString);}
-  nsString& operator+=(const char aChar) {return Append(PRUnichar(unsigned char(aChar)));}
+  nsString& operator+=(const char aChar) {
+    unsigned char theChar=(unsigned char)aChar;
+    return Append(PRUnichar(theChar));
+  }
   nsString& operator+=(const PRUnichar* aUCString) {return Append(aUCString);}
   nsString& operator+=(const PRUnichar aChar){return Append(aChar);}
   nsString& operator+=(const int anInt){return Append(anInt,10);}

xpcom/ds/nsString2.h

@@ -442,7 +442,10 @@ public:
   nsString& operator+=(const nsStr& aString){return Append(aString,aString.mLength);}
   nsString& operator+=(const nsString& aString){return Append(aString,aString.mLength);}
   nsString& operator+=(const char* aCString) {return Append(aCString);}
-  nsString& operator+=(const char aChar) {return Append(PRUnichar(unsigned char(aChar)));}
+  nsString& operator+=(const char aChar) {
+    unsigned char theChar=(unsigned char)aChar;
+    return Append(PRUnichar(theChar));
+  }
   nsString& operator+=(const PRUnichar* aUCString) {return Append(aUCString);}
   nsString& operator+=(const PRUnichar aChar){return Append(aChar);}
   nsString& operator+=(const int anInt){return Append(anInt,10);}

xpcom/string/obsolete/nsString2.h

@@ -442,7 +442,10 @@ public:
   nsString& operator+=(const nsStr& aString){return Append(aString,aString.mLength);}
   nsString& operator+=(const nsString& aString){return Append(aString,aString.mLength);}
   nsString& operator+=(const char* aCString) {return Append(aCString);}
-  nsString& operator+=(const char aChar) {return Append(PRUnichar(unsigned char(aChar)));}
+  nsString& operator+=(const char aChar) {
+    unsigned char theChar=(unsigned char)aChar;
+    return Append(PRUnichar(theChar));
+  }
   nsString& operator+=(const PRUnichar* aUCString) {return Append(aUCString);}
   nsString& operator+=(const PRUnichar aChar){return Append(aChar);}
   nsString& operator+=(const int anInt){return Append(anInt,10);}