fix(build): link math library for fractional-indexing on Linux/Android

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: andinux

Makefile

@@ -132,7 +132,7 @@ else ifeq ($(PLATFORM),android)
 	CURL_CONFIG = --host $(ARCH)-linux-$(ANDROID_ABI) --with-openssl=$(CURDIR)/$(OPENSSL_INSTALL_DIR) LDFLAGS="-L$(CURDIR)/$(OPENSSL_INSTALL_DIR)/lib" LIBS="-lssl -lcrypto" AR=$(BIN)/llvm-ar AS=$(BIN)/llvm-as CC=$(CC) CXX=$(BIN)/$(ARCH)-linux-$(ANDROID_ABI)-clang++ LD=$(BIN)/ld RANLIB=$(BIN)/llvm-ranlib STRIP=$(BIN)/llvm-strip
 	TARGET := $(DIST_DIR)/cloudsync.so
 	CFLAGS += -fPIC -I$(OPENSSL_INSTALL_DIR)/include
-	LDFLAGS += -shared -fPIC -L$(OPENSSL_INSTALL_DIR)/lib -lssl -lcrypto
+	LDFLAGS += -shared -fPIC -L$(OPENSSL_INSTALL_DIR)/lib -lssl -lcrypto -lm
 	STRIP = $(BIN)/llvm-strip --strip-unneeded $@
 else ifeq ($(PLATFORM),ios)
 	TARGET := $(DIST_DIR)/cloudsync.dylib
@@ -152,8 +152,8 @@ else ifeq ($(PLATFORM),ios-sim)
 	STRIP = strip -x -S $@
 else # linux
 	TARGET := $(DIST_DIR)/cloudsync.so
-	LDFLAGS += -shared -lssl -lcrypto
-	T_LDFLAGS += -lpthread
+	LDFLAGS += -shared -lssl -lcrypto -lm
+	T_LDFLAGS += -lpthread -lm
 	CURL_CONFIG = --with-openssl
 	STRIP = strip --strip-unneeded $@
 endif