diff --git a/modules/libreg/xpcom/nsRegistry.cpp b/modules/libreg/xpcom/nsRegistry.cpp
index cf99b460eff..d0a19f39314 100644
--- a/modules/libreg/xpcom/nsRegistry.cpp
+++ b/modules/libreg/xpcom/nsRegistry.cpp
@@ -1414,8 +1414,8 @@ NS_IMETHODIMP nsRegistry::UnescapeKey(PRUint8* escaped, PRUint32 termination, PR
         {
             if (e - b >= 2)
             {
-                char* c1 = strchr(sEscapeKeyHex, *(b++));
-                char* c2 = strchr(sEscapeKeyHex, *(b++));
+                const char* c1 = strchr(sEscapeKeyHex, *(b++));
+                const char* c2 = strchr(sEscapeKeyHex, *(b++));
                 if (c1 != nsnull
                     && c2 != nsnull)
                 {
diff --git a/xpcom/components/nsRegistry.cpp b/xpcom/components/nsRegistry.cpp
index cf99b460eff..d0a19f39314 100644
--- a/xpcom/components/nsRegistry.cpp
+++ b/xpcom/components/nsRegistry.cpp
@@ -1414,8 +1414,8 @@ NS_IMETHODIMP nsRegistry::UnescapeKey(PRUint8* escaped, PRUint32 termination, PR
         {
             if (e - b >= 2)
             {
-                char* c1 = strchr(sEscapeKeyHex, *(b++));
-                char* c2 = strchr(sEscapeKeyHex, *(b++));
+                const char* c1 = strchr(sEscapeKeyHex, *(b++));
+                const char* c2 = strchr(sEscapeKeyHex, *(b++));
                 if (c1 != nsnull
                     && c2 != nsnull)
                 {