build: Add SIMD optimizations to compare.c

Add SIMD (Single Instruction, Multiple Data) optimizations to the
compare.c file to improve performance. This includes vectorization
flags and architecture-specific optimizations to enhance the
processing of data in the comparison function. Additionally, the
implementation now dynamically selects an optimized code path based
on the size of the pattern data, ensuring efficient execution for
various scenarios.

By Lixfel

schemsearch-lib/build.rs

@@ -3,5 +3,9 @@ use cc;
 fn main() {
     cc::Build::new()
         .file("src/compare.c")
+        .flag("-ftree-vectorize")
+        .flag("-march=native")
+        .flag("-mtune=native")
+        .flag("-ffast-math")
         .compile("compare");
 }