diff --git a/rust.changes b/rust.changes
index 1ee581c..013bfe1 100644
--- a/rust.changes
+++ b/rust.changes
@@ -1,3 +1,10 @@
+-------------------------------------------------------------------
+Sat Feb 23 01:58:47 UTC 2019 - Luke Jones <jones_ld@protonmail.com>
+
+- Ensure install environment is the same as build environment to
+  prevent building everything twice (second time without correct
+  flags).
+
 -------------------------------------------------------------------
 Thu Jan 17 21:22:11 UTC 2019 - Luke Jones <jones_ld@protonmail.com>
 
diff --git a/rust.spec b/rust.spec
index 870da9b..386be0a 100644
--- a/rust.spec
+++ b/rust.spec
@@ -47,20 +47,33 @@
 %global rust_triple %{rust_arch}-unknown-linux-%{abi}
 # All sources and bootstraps are fetched form here
 %global dl_url https://static.rust-lang.org/dist
+
 # Rust doesn't function well when put in /usr/lib64
 %global common_libdir %{_prefix}/lib
 %global rustlibdir %{common_libdir}/rustlib
+
 # Use hardening ldflags.
 %global rustflags -Clink-arg=-Wl,-z,relro,-z,now
+
 # We occasionally need to bootstrap builds due to breakage etc. Rust only guarantees
 # v-1 will build v
 %bcond_with rust_bootstrap
+
 # Distro LLVM should be sufficient, this also cuts compile times byu almost half
 %if 0%{?suse_version} <= 1315
 %bcond_without bundled_llvm
 %else
 %bcond_with bundled_llvm
 %endif
+
+# Debuginfo can exhaust memory on these architecture workers
+%ifarch  %{arm} %{ix86}
+%define codegen_units --set codegen-units=4
+%define debug_info --disable-debuginfo --enable-debuginfo-only-std --disable-debuginfo-tools --disable-debuginfo-lines
+%else
+%define debug_info --enable-debuginfo --disable-debuginfo-only-std --enable-debuginfo-tools --disable-debuginfo-lines
+%endif
+
 Name:           rust
 Version:        1.32.0
 Release:        0
@@ -350,29 +363,29 @@ sed -i '1s|^|#!/bin/bash\n|' src/liblibc/ci/emscripten-entry.sh
 sed -i '1s|^|#!/bin/bash\n|' src/stdsimd/ci/run-docker.sh
 
 %build
+# Keep all the "export VARIABLE" together here, so they can be
+# cut&pasted to the %install section below.  And please keep them in
+# sync!  If the environments between build and install and different,
+# everything will be rebuilt during installation!
+
 # This should eventually migrate to distro policy
 # Enable optimization, debuginfo, and link hardening.
 export RUSTFLAGS="%{rustflags}"
 # Cargo use system libs
 export LIBGIT2_SYS_USE_PKG_CONFIG=1
 export LIBSSH2_SYS_USE_PKG_CONFIG=1
-
-# Debuginfo can exhaust memory on these architecture workers
-%ifarch  %{arm} %{ix86}
-%define codegen_units --set codegen-units=4
-%define debug_info --disable-debuginfo --enable-debuginfo-only-std --disable-debuginfo-tools --disable-debuginfo-lines
-%else
-%define debug_info --enable-debuginfo --disable-debuginfo-only-std --enable-debuginfo-tools --disable-debuginfo-lines
-%endif
+export CPPFLAGS="%{optflags}" # eliminate complain from RPMlint
 
 %configure \
   --disable-option-checking \
   --build=%{rust_triple} --host=%{rust_triple} --target=%{rust_triple} \
+  --enable-local-rust \
   --local-rust-root=%{rust_root} \
   --libdir=%{common_libdir} \
   --docdir=%{_docdir}/%{name} \
   %{!?with_bundled_llvm: --llvm-root=%{_prefix} --enable-llvm-link-shared} \
   --disable-codegen-tests \
+  --enable-optimize \
   --enable-docs \
   --enable-verbose-tests \
   --disable-jemalloc \
@@ -382,8 +395,6 @@ export LIBSSH2_SYS_USE_PKG_CONFIG=1
   --enable-vendor \
   --release-channel="stable"
 
-export CPPFLAGS="%{optflags}" # eliminate complain from RPMlint
-
 # We need less codegen units for these arches since the workers are running out of memory
 # This means we must apply a minimum of 2 CPUs to a worker in constraints.
 %ifarch  %{arm} %{ix86}
@@ -394,6 +405,19 @@ sed -i -e "s|#codegen-units = 1|codegen-units = 2|" config.toml
 ./x.py doc -v
 
 %install
+# Keep all the "export VARIABLE" together here, so they can be
+# cut&pasted to the %install section below.  And please keep them in
+# sync!  If the environments between build and install and different,
+# everything will be rebuilt during installation!
+
+# This should eventually migrate to distro policy
+# Enable optimization, debuginfo, and link hardening.
+export RUSTFLAGS="%{rustflags}"
+# Cargo use system libs
+export LIBGIT2_SYS_USE_PKG_CONFIG=1
+export LIBSSH2_SYS_USE_PKG_CONFIG=1
+export CPPFLAGS="%{optflags}" # eliminate complain from RPMlint
+
 DESTDIR=%{buildroot} python3 ./x.py install
 DESTDIR=%{buildroot} python3 ./x.py install src