partial-inlining: disable partial-inlining if gcc>=8.2.1

Apply flag -fno-partial-inlining on default optimization if and only if
gcc version >= 8.2.1 (this is the current ver on Fedora and Ubuntu).
This is done to avoid a bug that causes arithmetic calculations to fail
if the following conditions are met:
1. TEST_FRAMEWORK on
2. DONT_OPTIMIZE off
3. Fedora and Ubuntu
4. GCC 8.2.1
5. There must exist a certain combination of multithreading.
6. Optimization level -O2 and -O3
7. Flag -fpartial-inline activated (default when optimization level>=2)
The following link points to a similar gcc bug reported in 2015. This leads me
to believe the bug has regressed. Note I am not able to replicate this bug
in an environment other than Asterisk + Test Framework + Test_cel because the
multithreading combination that causes it seems to be unique. Therefore I
am temporarily abandoning any thoughts of reporting the new occurrence of this
bug to gcc.gnu.org.  https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65307

Change-Id: Ibd1afe60e0a38b88e85fdcd9b051004601c2f102

Makefile.rules

@@ -70,6 +70,12 @@ ifneq ($(findstring darwin,$(OSARCH)),)
   endif
 endif
 
+# gcc version 8.2.1 and above must have partial-inlining disabled to avoid documented bug
+GCC_VER_GTE821:=$(shell expr `gcc --version | grep ^gcc | cut -d ' ' -f 3 | sed -e 's/\.\([0-9][0-9]\)/\1/g' -e 's/\.\([0-9]\)/0\1/g' -e 's/^[0-9]\{3,4\}$$/&00/'` \>= 80201)
+ifeq ($(GCC_VER_GTE821),1)
+    OPTIMIZE+=-fno-partial-inlining
+endif
+
 ifeq ($(findstring DONT_OPTIMIZE,$(MENUSELECT_CFLAGS))$(AST_CODE_COVERAGE),no)
     _ASTCFLAGS+=$(OPTIMIZE)
 else