Restore conditional iperf3 build; enable force-build on Debuntu #1441

unibuild-order

@@ -20,6 +20,10 @@ changecom()dnl
 
 # GENERAL-PURPOSE MACROS
 
+# Setting this to 1 forces builds of all packages on Debian systems.
+# See commentary surrounding iperf3.
+define(BUILD_ALL_DEB,1)
+
 # Setting this to zero removes all tools that depend on OWAMP, which
 # is built in a separate repository.  The only time you'd want to do
 # this is when doing unrelated development.
@@ -124,7 +128,16 @@ ifelse(DISTRO/eval(MAJOR <= 18),Ubuntu/1,,      # Doesn't build on U18, TODO: no
        HAVE_ETHR,1,ethr)                        # But D10 build can be used on U18 and up
 
 iperf
-iperf3
+
+# The Debian and Ubuntu builds look to minimize build time because
+# non-x86 architectures have to be built under an emulator that runs
+# at 20% the speed of native.  Binary builds get re-used between
+# distributions.
+ifelse(FAMILY/eval(MAJOR == 12),Debian/1,iperf3,  # D12 binary is reused on D11.
+       DISTRO/eval(MAJOR == 20),Ubuntu/1,iperf3,  # U20 binary is reused on 22.
+       DISTRO/eval(MAJOR == 24),Ubuntu/1,iperf3,  # The jury is still out on U24, so build it.
+       FAMILY/BUILD_ALL_DEB,Debian/0,,            # Diable all else in the Debian family unless forced
+       iperf3)                                    # Always build on non-Debuntu.
 nuttcp
 
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