Reapply "Refactor build.rs"

This reverts commit 7d56656.

build.rs

@@ -37,14 +37,9 @@ fn run() -> Result<(), Box<dyn Error>> {
     println!("cargo:rerun-if-changed=wrapper.h");
     println!("cargo:rerun-if-changed=cc");
     println!("cargo:rustc-link-search={}", llvm_config("--libdir")?);
-    println!("cargo:rustc-link-lib=static=LLVMCore");
-    println!("cargo:rustc-link-lib=static=LLVMSupport");
-    println!("cargo:rustc-link-lib=static=LLVMTableGen");
 
     for name in llvm_config("--libnames")?.trim().split(' ') {
-        if let Some(name) = trim_library_name(name) {
-            println!("cargo:rustc-link-lib={}", name);
-        }
+        println!("cargo:rustc-link-lib={}", parse_library_name(name)?);
     }
 
     for flag in llvm_config("--system-libs")?.trim().split(' ') {
@@ -60,14 +55,7 @@ fn run() -> Result<(), Box<dyn Error>> {
             );
             println!(
                 "cargo:rustc-link-lib={}",
-                path.file_name()
-                    .unwrap()
-                    .to_str()
-                    .unwrap()
-                    .split_once('.')
-                    .unwrap()
-                    .0
-                    .trim_start_matches("lib")
+                parse_library_name(path.file_name().unwrap().to_str().unwrap())?
             );
         } else {
             println!("cargo:rustc-link-lib={}", flag);
@@ -144,10 +132,8 @@ fn llvm_config(argument: &str) -> Result<String, Box<dyn Error>> {
     .to_string())
 }
 
-fn trim_library_name(name: &str) -> Option<&str> {
-    if let Some(name) = name.strip_prefix("lib") {
-        name.strip_suffix(".a")
-    } else {
-        None
-    }
+fn parse_library_name(name: &str) -> Result<&str, String> {
+    name.strip_prefix("lib")
+        .and_then(|name| name.split('.').next())
+        .ok_or_else(|| format!("failed to parse library name: {}", name))
 }