Bug#877063: libitpp FTBFS on i386 with gcc 7

[Adrian Bunk]

Source: libitpp
Version: 4.3.1-7
Severity: serious
Tags: patch

https://tests.reproducible-builds.org/debian/rb-pkg/unstable/i386/libitpp.html

...
[----------] 1 test from Rand
[ RUN      ] Rand.All
libitpp_4.3.1-7/gtests/rand_test.cpp:277: Failure
The difference between 2.9631003166431262 and ric_rng() is 8.8817841970012523e-16, which exceeds eps, where
2.9631003166431262 evaluates to 2.9631003166431262,
ric_rng() evaluates to 2.9631003166431253, and
eps evaluates to 4.4408920985006262e-16.
[  FAILED  ] Rand.All (1 ms)
[----------] 1 test from Rand (1 ms total)
...
[  PASSED  ] 77 tests.
[  FAILED  ] 1 test, listed below:
[  FAILED  ] Rand.All

 1 FAILED TEST
debian/rules:16: recipe for target 'override_dh_auto_build-arch' failed
make[1]: *** [override_dh_auto_build-arch] Error 1


If the exact result is required here, the following fixes it:

--- debian/rules.old	2017-09-28 09:37:10.000000000 +0000
+++ debian/rules	2017-09-28 09:37:58.000000000 +0000
@@ -1,7 +1,13 @@
 #!/usr/bin/make -f
 
+DEB_HOST_ARCH ?= $(shell dpkg-architecture -qDEB_HOST_ARCH)
 DEB_HOST_MULTIARCH ?= $(shell dpkg-architecture -qDEB_HOST_MULTIARCH)
 
+ifneq (,$(findstring $(DEB_HOST_ARCH), i386))
+    export DEB_CFLAGS_MAINT_APPEND = -ffloat-store
+    export DEB_CXXFLAGS_MAINT_APPEND = -ffloat-store
+endif
+
 DEBUG_PACKAGE = $(shell awk '/^Package/ && /-dbg *$$/ { print $$2 }' debian/control)
 %:
 	VERBOSE=1 dh $@ --parallel --builddirectory=build