config: Remove unused define for os uClibc

__NO_STRING_INLINES was removed from uClibc around 2004 so has no
effect.

libstdc++-v3/ChangeLog:

2018-10-01  Bernhard Reutner-Fischer  <aldot@gcc.gnu.org>

        * config/os/uclibc/os_defines.h (__NO_STRING_INLINES): Delete.

From-SVN: r264783

libstdc++-v3/ChangeLog

+2018-10-01  Bernhard Reutner-Fischer  <aldot@gcc.gnu.org>
+
+	* config/os/uclibc/os_defines.h (__NO_STRING_INLINES): Delete.
+
 2018-10-01  Gerald Pfeifer  <gerald@pfeifer.com>
 
 	* doc/xml/manual/allocator.xml: Adjust link to "Reconsidering
@@ -13,7 +17,7 @@
 	to https.
 
 2018-09-30  Gerald Pfeifer  <gerald@pfeifer.com>
-	
+
 	* doc/xml/manual/policy_data_structures_biblio.xml: Update
 	link to Microsoft Component Model Object Technologies.
 

libstdc++-v3/config/os/uclibc/os_defines.h

@@ -38,7 +38,4 @@
 
 #include <features.h>
 
-// We must not see the optimized string functions GNU libc defines.
-#define __NO_STRING_INLINES
-
 #endif