native/nativesdk: Stop overriding unprefixed *FLAGS variables

We're currently encouraging an "arms race" with the FLAGS variables since
a recipe might want to set a specific flag for all variants but to do so,
+= won't work due to the assignment in the native/nativesdk class files. This
means recipes are using append.

Since the default variables are constructed out of TARGET_XXX variables and
we redefine these, there is no need to re-define the un-prefixed variables. If
we drop that, the += appends and similar work and recipes don't have to resort
to append.

Change the classes and cleanup a number of recipes to adapt to the change. This
change will result in some flags appearing to some native/nativesdk variants
but that is probably what was originally expected anyway.

(From OE-Core rev: a157b2f9d93428ca21265cc860a3b58b3698b3aa)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/python/python3-bcrypt_4.1.3.bb

@@ -4,7 +4,7 @@ LIC_FILES_CHKSUM = "file://LICENSE;md5=8f7bb094c7232b058c7e9f2e431f389c"
 HOMEPAGE = "https://pypi.org/project/bcrypt/"
 
 DEPENDS += "python3-cffi-native"
-LDFLAGS:append = "${@bb.utils.contains('DISTRO_FEATURES', 'ptest', ' -fuse-ld=bfd', '', d)}"
+LDFLAGS += "${@bb.utils.contains('DISTRO_FEATURES', 'ptest', '-fuse-ld=bfd', '', d)}"
 
 SRC_URI[sha256sum] = "2ee15dd749f5952fe3f0430d0ff6b74082e159c50332a1413d51b5689cf06623"
 

meta/recipes-devtools/python/python3-maturin_1.6.0.bb

@@ -9,7 +9,7 @@ SRC_URI[sha256sum] = "b955025c24c8babc808db49e0ff90db8b4b1320dcc16b14eb261328417
 
 S = "${WORKDIR}/maturin-${PV}"
 
-CFLAGS:append = " -fdebug-prefix-map=${CARGO_HOME}=${TARGET_DBGSRC_DIR}/cargo_home"
+CFLAGS += "-fdebug-prefix-map=${CARGO_HOME}=${TARGET_DBGSRC_DIR}/cargo_home"
 
 DEPENDS += "\
     python3-setuptools-rust-native \

meta/recipes-devtools/python/python3_3.12.4.bb

@@ -118,7 +118,7 @@ ${@bb.utils.contains('PACKAGECONFIG', 'tk', '', '_tkinter', d)}
 EOF
 }
 
-CPPFLAGS:append = " -I${STAGING_INCDIR}/ncursesw -I${STAGING_INCDIR}/uuid"
+CPPFLAGS += "-I${STAGING_INCDIR}/ncursesw -I${STAGING_INCDIR}/uuid"
 
 # COMPILEALL_OPTS= ensures that .pyc are not compiled in parallel
 # This was found to lock up builds, break reproducibility, and produce strange file ownership