libraries: honour SPC_DEFAULT_CFLAGS/CXXFLAGS/LDFLAGS and bug fixes

bzip2, fastlz, jbig, qdbm: thread SPC_DEFAULT_CFLAGS into the
hand-rolled Makefile patches and shell compile commands. Backward
compatible when the env var is empty.

icu: append SPC_DEFAULT_CXXFLAGS/LDFLAGS to runConfigureICU's CXXFLAGS
and LDFLAGS so user flags reach the bundled cxx invocation.

openssl: append user CFLAGS/LDFLAGS after the target name on Configure
so options like -flto and -fprofile-* reach the openssl build.

libheif: rewrite libheif 1.22+'s C-incompatible
`struct heif_bad_pixel { uint32_t row; uint32_t column; };` as a
typedef so C consumers compile.

ncurses: filter the clang/zig-cc "N warning(s) generated." stdout line
out of MKlib_gen.sh's preprocessor pipe before sed turns it into
invalid C in lib_gen.c.

libaom: detect target CPU from SystemTarget instead of hard-coding
generic, fall back to generic only when neither nasm nor yasm is
available, and turn off examples/tests/tools/docs.

src/Package/Library/fastlz.php

@@ -18,9 +18,11 @@ class fastlz
     {
         $cc = getenv('CC') ?: 'cc';
         $ar = getenv('AR') ?: 'ar';
+        $extra = trim((string) getenv('SPC_DEFAULT_CFLAGS'));
+        $extra = $extra !== '' ? $extra . ' -fPIC' : '-O3 -fPIC';
 
         shell()->cd($lib->getSourceDir())->initializeEnv($lib)
-            ->exec("{$cc} -c -O3 -fPIC fastlz.c -o fastlz.o")
+            ->exec("{$cc} -c {$extra} fastlz.c -o fastlz.o")
             ->exec("{$ar} rcs libfastlz.a fastlz.o");
 
         // Copy header file