NaCl's newlib doesn't have std::to_string().

src/Shader.cpp

@@ -27,6 +27,10 @@
 #include <fstream>
 #include <Utility/Assert.h>
 
+#ifdef CORRADE_TARGET_NACL_NEWLIB
+#include <sstream>
+#endif
+
 /* libgles-omap3-dev_4.03.00.02-r15.6 on BeagleBoard/Ångström linux 2011.3 doesn't have GLchar */
 #ifdef MAGNUM_TARGET_GLES
 typedef char GLchar;
@@ -101,9 +105,20 @@ Shader& Shader::operator=(Shader&& other) {
 
 Shader& Shader::addSource(std::string source) {
     if(!source.empty()) {
+        #ifdef CORRADE_TARGET_NACL_NEWLIB
+        std::ostringstream converter;
+        converter << (sources.size()+1)/2;
+        #endif
+
         /* Fix line numbers, so line 41 of third added file is marked as 3(41).
            Source 0 is the #version string added in constructor. */
-        sources.push_back("#line 1 " + std::to_string((sources.size()+1)/2) + '\n');
+        sources.push_back("#line 1 " +
+            #ifndef CORRADE_TARGET_NACL_NEWLIB
+            std::to_string((sources.size()+1)/2) +
+            #else
+            converter.str() +
+            #endif
+            '\n');
         sources.push_back(std::move(source));
     }