diff --git a/macros.build-constraints b/macros.build-constraints
new file mode 100644
index 0000000..db99418
--- /dev/null
+++ b/macros.build-constraints
@@ -0,0 +1,42 @@
+# Macros to constrain resource use during the build process
+
+# outputs build flag overrides to be used in conjunction with
+# %%make_build, %%cmake_build etc.
+#
+# if no override is needed, this macro outputs nothing
+#
+# - m   memory limit in MBs per core; default is 1024
+#
+# Usage:
+# e.g. %make_build %{limit_build -m 2048}
+#   => /usr/bin/make -O -j16 V=1 VERBOSE=1
+#      %make_build %{limit_build -m 40960}
+#   => /usr/bin/make -O -j16 V=1 VERBOSE=1 -j1
+# 
+%limit_build(m:) %{lua:
+  local mem_per_process=rpm.expand("%{-m*}")
+  if mem_per_process == "" then
+    mem_per_process = 1024
+  else
+    mem_per_process = tonumber(mem_per_process)
+  end
+  local mem_total = 0
+  for line in io.lines('/proc/meminfo') do
+    if line:sub(1, 9) == "MemTotal:" then
+      local tokens = {}
+      for token in line:gmatch("%w+") do
+        tokens[#tokens + 1] = token
+      end
+      mem_total = tonumber(tokens[2])
+      break
+    end
+  end
+  local max_jobs = mem_total // (mem_per_process * 1024)
+  if max_jobs < 1 then
+    max_jobs = 1
+  end
+  cur_max_jobs=tonumber(rpm.expand("%{_smp_build_ncpus}"))
+  if cur_max_jobs > max_jobs then
+    print("-j" .. max_jobs)
+  end
+}
diff --git a/redhat-rpm-config.spec b/redhat-rpm-config.spec
index 2dbda4a..9817f2e 100644
--- a/redhat-rpm-config.spec
+++ b/redhat-rpm-config.spec
@@ -6,8 +6,8 @@
 
 Summary: Red Hat specific rpm configuration files
 Name: redhat-rpm-config
-Version: 175
-Release: 1.0.riscv64%{?dist}
+Version: 176
+Release: 3%{?dist}
 # No version specified.
 License: GPL+
 URL: https://src.fedoraproject.org/rpms/redhat-rpm-config
@@ -36,12 +36,13 @@ Source104: macros.ldc-srpm
 Source105: macros.valgrind-srpm
 
 # Other misc macros
-Source150: macros.dwz
-Source151: macros.kmp
-Source152: macros.vpath
+Source150: macros.build-constraints
+Source151: macros.dwz
+Source152: macros.fedora-misc
 Source153: macros.forge
-Source154: macros.ldconfig
-Source155: macros.fedora-misc
+Source154: macros.kmp
+Source155: macros.ldconfig
+Source156: macros.vpath
 
 # Build policy scripts
 # this comes from https://github.com/rpm-software-management/rpm/pull/344
@@ -111,6 +112,7 @@ Requires: perl-srpm-macros
 Requires: python-srpm-macros >= 3-46
 Requires: qt5-srpm-macros
 Requires: rust-srpm-macros
+Requires: rpmautospec-rpm-macros
 
 Requires: rpm >= 4.11.0
 Requires: dwz >= 0.4
@@ -188,11 +190,12 @@ install -p -m 644 -t %{buildroot}%{_rpmluadir}/fedora/srpm forge.lua
 %{rrcdir}/brp-ldconfig
 %{_fileattrsdir}/*.attr
 %{_rpmconfigdir}/macros.d/macros.*-srpm
+%{_rpmconfigdir}/macros.d/macros.build-constraints
 %{_rpmconfigdir}/macros.d/macros.dwz
+%{_rpmconfigdir}/macros.d/macros.fedora-misc
 %{_rpmconfigdir}/macros.d/macros.forge
 %{_rpmconfigdir}/macros.d/macros.ldconfig
 %{_rpmconfigdir}/macros.d/macros.vpath
-%{_rpmconfigdir}/macros.d/macros.fedora-misc
 %dir %{_rpmluadir}/fedora
 %dir %{_rpmluadir}/fedora/srpm
 %dir %{_rpmluadir}/fedora/rpm
@@ -213,8 +216,18 @@ install -p -m 644 -t %{buildroot}%{_rpmluadir}/fedora/srpm forge.lua
 %{_rpmconfigdir}/macros.d/macros.kmp
 
 %changelog
-* Mon Apr 26 2021 David Abdurachmanov <david.abdurachmanov@gmail.com> - 175-1.0.riscv64
-- Add riscv64 to %%mono_arches
+* Sun Aug 15 2021 Michel Alexandre Salim <salimma@fedoraproject.org> - 176-3
+- Fix macros.build-constraints' %%limit_build
+  - number of CPUs will never be set to less than 1
+  - this now outputs build flag overrides to be used with %%make_build etc.
+  - add documentation
+
+* Sat Jul 24 2021 Michel Alexandre Salim <salimma@fedoraproject.org> - 176-2
+- Add macros.build-constraints
+- Keep the misc macros in alphabetical order
+
+* Thu Apr 29 2021 Stephen Coady <scoady@redhat.com> - 176-1
+- Add Requires: rpmautospec-rpm-macros
 
 * Wed Mar 10 2021 Kalev Lember <klember@redhat.com> - 175-1
 - BRP Python Bytecompile: Avoid hardcoding /usr/bin prefix for python