Drop no longer relevant files from .gitignore

Author: hebasto

.gitignore

@@ -42,8 +42,6 @@ coverage.*.html
 *.gcno
 *.gcov
 
-src/libsecp256k1-config.h
-src/libsecp256k1-config.h.in
 build-aux/ar-lib
 build-aux/config.guess
 build-aux/config.sub
@@ -58,5 +56,4 @@ build-aux/m4/ltversion.m4
 build-aux/missing
 build-aux/compile
 build-aux/test-driver
-src/stamp-h1
 libsecp256k1.pc