diff --git a/MozillaFirefox.changes b/MozillaFirefox.changes
index 807a8af..edb6e20 100644
--- a/MozillaFirefox.changes
+++ b/MozillaFirefox.changes
@@ -1,3 +1,13 @@
+-------------------------------------------------------------------
+Fri Jan 11 15:07:14 UTC 2019 - Martin Liška <mliska@suse.cz>
+
+- Set %clang_build to false on all architectures
+- Do not use -fno-delete-null-pointer-checks and -fno-strict-aliasing:
+  it should not be needed.
+- Do not overwrite enable-optimize and when possible
+  enable --enable-debug-symbols.
+- Add -v to mach in order to make build verbose.
+
 -------------------------------------------------------------------
 Wed Jan  9 22:40:14 UTC 2019 - astieger@suse.com
 
diff --git a/MozillaFirefox.spec b/MozillaFirefox.spec
index 0651caf..2ff68c9 100644
--- a/MozillaFirefox.spec
+++ b/MozillaFirefox.spec
@@ -13,7 +13,7 @@
 # license that conforms to the Open Source Definition (Version 1.9)
 # published by the Open Source Initiative.
 
-# Please submit bugfixes or comments via http://bugs.opensuse.org/
+# Please submit bugfixes or comments via https://bugs.opensuse.org/
 #
 
 
@@ -27,14 +27,8 @@
 %define releasedate    20190108160530
 %define source_prefix  firefox-%{orig_version}
 
-# use clang (upstream default since 64.0)
-%if 0%{?suse_version} > 1320
-%define clang_build 1
-%endif
-# Except on %%arm due to large ld memory requirements
-%ifarch %arm
+# always build with GCC as SUSE Security Team requires that
 %define clang_build 0
-%endif
 
 # PIE, full relro
 %define build_hardened 1
@@ -313,13 +307,6 @@ export CC=gcc
 export CXX=g++
 %endif
 %endif
-export CFLAGS="%{optflags} -fno-strict-aliasing"
-# boo#986541: add -fno-delete-null-pointer-checks for gcc6
-%if 0%{?clang_build} == 0
-%if 0%{?suse_version} > 1320
-export CFLAGS="$CFLAGS -fno-delete-null-pointer-checks"
-%endif
-%endif
 %ifarch %arm %ix86
 # Limit RAM usage during link
 export LDFLAGS="${LDFLAGS} -Wl,--no-keep-memory -Wl,--reduce-memory-overheads"
@@ -349,13 +336,11 @@ ac_add_options --enable-default-toolkit=cairo-gtk3
 %if 0%{?suse_version} >= 1550
 ac_add_options --disable-gconf
 %endif
-# gcc7 (boo#104105)
-%if 0%{?suse_version} > 1320
-ac_add_options --enable-optimize="-g -O2"
-%endif
 # bmo#1441155 - Disable the generation of Rust debug symbols on Linux32
 %ifarch %ix86 %arm
 ac_add_options --disable-debug-symbols
+%else
+ac_add_options --enable-debug-symbols
 %endif
 %if 0%{?suse_version} > 1549
 %ifnarch aarch64 ppc64 ppc64le
@@ -400,7 +385,7 @@ ac_add_options --with-arch=armv7-a
 ac_add_options --disable-webrtc
 %endif
 EOF
-./mach build
+./mach build -v
 
 %install
 cd $RPM_BUILD_DIR/obj