Update dependency on cc (previously gcc) crate

Rename the gcc crate to cc per alexcrichton/cc-rs@410992f, and update
the one breaking change from the `Config` struct to `Build`, per
alexcrichton/cc-rs@dc4bfb4.

The primary impetus for this change is to pull over
alexcrichton/cc-rs@2b1ce98, which *drastically* speeds up build times of
rocksdb-sys (20m to 1m, on my machine).

librocksdb-sys/Cargo.toml

@@ -22,5 +22,5 @@ libc = "0.2"
 const-cstr = "0.2"
 
 [build-dependencies]
-gcc = { version = "0.3", features = ["parallel"] }
+cc = { version = "1.0", features = ["parallel"] }
 make-cmd = "0.1"

librocksdb-sys/build.rs

@@ -1,4 +1,4 @@
-extern crate gcc;
+extern crate cc;
 
 use std::fs;
 
@@ -30,7 +30,7 @@ fn build_rocksdb() {
     println!("cargo:rerun-if-changed=build.rs");
     println!("cargo:rerun-if-changed=rocksdb/");
 
-    let mut config = gcc::Config::new();
+    let mut config = cc::Build::new();
     config.include("rocksdb/include/");
     config.include("rocksdb/");
     config.include("rocksdb/third-party/gtest-1.7.0/fused-src/");
@@ -115,7 +115,7 @@ fn build_rocksdb() {
 }
 
 fn build_snappy() {
-    let mut config = gcc::Config::new();
+    let mut config = cc::Build::new();
     config.include("snappy/");
     config.include(".");