[cxx-interop] Fix CxxStdlib build error on CentOS

egorzhdan · egorzhdan · commit 7774650db1c7 · 2023-04-13T13:42:46.000+01:00
This fixes a build failure that started occurring on CentOS after #65057: ``` error: cannot find 'strlen' in scope ``` rdar://107987115
diff --git a/stdlib/public/Cxx/std/String.swift b/stdlib/public/Cxx/std/String.swift
@@ -33,7 +33,7 @@ extension std.string {
       return
     }
 
-    let len = strlen(str)
+    let len = UTF8._nullCodeUnitOffset(in: str)
     for i in 0..<len {
       let char = UInt8(str[i])
       self.push_back(value_type(bitPattern: char))

Original file line number	Diff line number	Diff line change
`@@ -33,7 +33,7 @@ extension std.string {`
`33`	`33`	`return`
`34`	`34`	`}`
`35`	`35`
`36`		`- let len = strlen(str)`
	`36`	`+ let len = UTF8._nullCodeUnitOffset(in: str)`
`37`	`37`	`for i in 0..<len {`
`38`	`38`	`let char = UInt8(str[i])`
`39`	`39`	`self.push_back(value_type(bitPattern: char))`