diff --git a/gnu/packages/java-bootstrap.scm b/gnu/packages/java-bootstrap.scm
index bce7b4fbfc6..7a6251611ee 100644
--- a/gnu/packages/java-bootstrap.scm
+++ b/gnu/packages/java-bootstrap.scm
@@ -161,7 +161,11 @@ language.")
                             (assoc-ref %build-inputs "classpath"))
              "--disable-int-caching"
              "--enable-runtime-reloc-checks"
-             "--enable-ffi")
+             "--enable-ffi"
+             ,(string-append
+               "CFLAGS=-g -O2"
+               " -Wno-error=implicit-function-declaration"
+               " -Wno-error=incompatible-pointer-types"))
        #:phases
        ,(if (string-prefix? "aarch64" (or (%current-system)
                                           (%current-target-system)))