[Android] ANIKETultimate:
I found out the issue. In aosp_sprout4.mk, the call to $(call inherit-product, device/google/sprout-common/sprout.mk) was after the declarations. The call also inherits from full_base_telephony.mk and creates the error.

Moved the call to the start of the file, and it worked.

However, I'm now stuck at this error -

[ 0% 1/5932] Target cache fs image: out/target/product/sprout4/cache.img
FAILED: out/target/product/sprout4/cache.img
/bin/bash -c "(mkdir -p out/target/product/sprout4/cache ) && (mkdir -p out/target/product/sprout4/obj/PACKAGING/cache_intermediates && rm -rf out/target/product/sprout4/obj/PACKAGING/cache_intermediates/cache_image_info.txt ) && (echo \"ext_mkuserimg=mkuserimg.sh\" >> out/target/product/sprout4/obj/PACKAGING/cache_intermediates/cache_image_info.txt ) && (echo \"fs_type=ext4\" >> out/target/product/sprout4/obj/PACKAGING/cache_intermediates/cache_image_info.txt ) && (echo \"system_size=956964608\" >> out/target/product/sprout4/obj/PACKAGING/cache_intermediates/cache_image_info.txt ) && (echo \"userdata_size=2147483648\" >> out/target/product/sprout4/obj/PACKAGING/cache_intermediates/cache_image_info.txt ) && (echo \"cache_fs_type=ext4\" >> out/target/product/sprout4/obj/PACKAGING/cache_intermediates/cache_image_info.txt ) && (echo \"cache_size=134217728\" >> out/target/product/sprout4/obj/PACKAGING/cache_intermediates/cache_image_info.txt ) && (echo \"extfs_sparse_flag=-s\" >> out/target/product/sprout4/obj/PACKAGING/cache_intermediates/cache_image_info.txt ) && (echo \"squashfs_sparse_flag=-s\" >> out/target/product/sprout4/obj/PACKAGING/cache_intermediates/cache_image_info.txt ) && (echo \"selinux_fc=out/target/product/sprout4/obj/ETC/file_contexts.bin_intermediates/file_contexts.bin\" >> out/target/product/sprout4/obj/PACKAGING/cache_intermediates/cache_image_info.txt ) && (echo \"skip_fsck=true\" >> out/target/product/sprout4/obj/PACKAGING/cache_intermediates/cache_image_info.txt ) && (PATH=out/host/linux-x86/bin/:\$PATH ./build/tools/releasetools/build_image.py out/target/product/sprout4/cache out/target/product/sprout4/obj/PACKAGING/cache_intermediates/cache_image_info.txt out/target/product/sprout4/cache.img out/target/product/sprout4/system ) && (size=\$(for i in out/target/product/sprout4/cache.img; do stat --format \"%s\" \"\$i\" | tr -d '\\n'; echo +; done; echo 0); total=\$(( \$( echo \"\$size\" ) )); printname=\$(echo -n \"out/target/product/sprout4/cache.img\" | tr \" \" +); img_blocksize=135168; twoblocks=\$((img_blocksize * 2)); onepct=\$(((((138412032 / 100) - 1) / img_blocksize + 1) * img_blocksize)); reserve=\$((twoblocks > onepct ? twoblocks : onepct)); maxsize=\$((138412032 - reserve)); echo \"\$printname maxsize=\$maxsize blocksize=\$img_blocksize total=\$total reserve=\$reserve\"; if [ \"\$total\" -gt \"\$maxsize\" ]; then echo \"error: \$printname too large (\$total > [138412032 - \$reserve])\"; false; elif [ \"\$total\" -gt \$((maxsize - 32768)) ]; then echo \"WARNING: \$printname approaching size limit (\$total now; limit \$maxsize)\"; fi )"
error: failed to build out/target/product/sprout4/cache.img from out/target/product/sprout4/cache
Running: mkuserimg.sh -s out/target/product/sprout4/cache out/target/product/sprout4/cache.img ext4 cache 134217728 -D out/target/product/sprout4/system -L cache out/target/product/sprout4/obj/ETC/file_contexts.bin_intermediates/file_contexts.bin
make_ext4fs -s -T -1 -S out/target/product/sprout4/obj/ETC/file_contexts.bin_intermediates/file_contexts.bin -L cache -l 134217728 -a cache out/target/product/sprout4/cache.img out/target/product/sprout4/cache out/target/product/sprout4/system
critical error: ext4_create_fs_aux_info: filesystem size too small
Creating filesystem with parameters:
Size: 134217728
Block size: 4096
Blocks per group: 32768
Inodes per group: 8192
Inode size: 256
Journal blocks: 1024
Label: cache